Prime Minister Chris Hipkins says there is a need for "transparency and vigilance" around lobbyists and their relationships with politicians.
His comments come in light of an RNZ investigation by Guyon Espiner which revealed his chief of staff, Andrew Kirton, was previously part of a lobbying firm which worked for alcohol companies which pushed back against a proposed container return scheme.
Kirton resigned from that role on 31 January, one day before taking the job as Hipkins' chief of staff.
Just last week, six weeks after Kirton started in the prime minister's office, the government announced it would delay the container return scheme.
However, Hipkins told Morning Report the scheme had already been "offered up for reprioritisation" by Environment Minister David Parker, before Kirton started working in the Beehive.
"In terms of the decision around reprioritisation, that went through Cabinet more recently, but it was on the list for reprioritisation before Andrew Kirton started working for me."
On the issue of lobbyists taking on roles with politicians or vice versa, he said it was important that people were clear about their shift and "that they dispense of any ongoing commitments or obligations or previous work before they take up any roles".
"I'm absolutely certain that Andrew Kirton has done that. Part of his taking on the job was that he had to dispense of any remaining kind of commitments he had to any of the clients he had worked with previously and I'm confident he has done that."
While there was "a need for transparency and vigilance" around lobbyists, he said it had proved challenging to deal with in Parliament before.
"I'm not saying we've got it completely right now. We've looked at a bill, for example, early on out of the Key government, that would've had more transparency around lobbying. One of the difficulties there is how you actually draw the distinction between people's lobbying and people's regular day to day employment.
"We've released ministerial diaries so people can see who ministers are meeting with. That certainly is one of the reasons why we get more questions about this because it makes it clear who ministers are meeting with and when."
However, RNZ investigate reporter Guyon Espiner told Morning Report the idea of transparency was open for debate.
"I mean they talk about the diaries being available on the ministerial website - yeah they are, but you meet with a lobbyist, you've got no idea as a member of the public who they're actually working for.
"It took these 70-plus OIA requests to find out who these clients are [for the investigative RNZ series]. So you might know they're meeting with someone who works in a lobbying firm, you've got zero idea what clients they are actually working for.
"A lot of these people are also in media roles, giving media commentary, and the public at large have no idea who these clients are. Then it emerges that the prime minister's own chief of staff has lobbied for these alcohol companies, and we've got no idea of knowing that unless we'd done these OIAs."
On the other hand, Hipkins believed lobbying companies brought in people like former politicians so "they feel that they are better able to [have] input into the decision-making process" by having a greater understanding of how the government works.
"If you look at the points about where they are making an input, it's often about how to be effective in doing things anyone can do, anyone can make a submission to a select committee."
Speaking about the stand-down periods between shifting between jobs in lobbying and politics, he said he "wouldn't completely rule out doing some more in this space in the future", but it had not been a high priority for him.
Most developed countries have a stand-down period for such role moves, but New Zealand is part of small group that doesn't.
"The OECD did a study of 41 countries and in that study nine of them, and New Zealand was one of them, that didn't have this [stand-down period]," Espiner said.
"In Canada, it's five years, in Australia, it's 18 months. Most of these developed countries - the US has it as well, as does Germany and Spain - have a cool-off period so you're not taking hot information, if you like, across with you, and that according to the OECD is one of the major conflict of interest situations that you get."
Hipkins later told reporters the timing of Kirton's appointment to the role so close to the time of the container deposit scheme and ongoing alcohol reform work being ditched was an "absolute coincidence".
"In terms of the reprioritisation of the container deposit scheme that was already in train," he said.
"In terms of the work around alcohol reform, we hadn't actually made decisions in terms of what was going to progress and the speed with which different parts of that were going to progress - and we now have."
The decisions had been made at Cabinet, which Kirton would not be present for, he said.
"I'm absolutely confident that Andrew Kirton has left behind all of the lobbying work that he was doing. It was one of the conditions of taking up the job that he had to discharge any remaining obligations that he had ... I'm confident that he did that."
He said it was always going to be challenging finding someone for the role of chief of staff in the middle of a government term.
"In filling a job like chief of staff, you are going to be looking for people who do understand the system of government, who do have some history of it, and who can step into the job on day one and start working effectively.
"I guess one of the challenges of recruiting in government as opposed to recruiting in opposition is that people are more likely to be going directly from one job to another.
"Whoever you recruit, they're most likely to have been in employment of some description. The key issue is how you manage any potential or perceived conflicts. I'm absolutely confident that both in terms of real and perception, we've been able to manage those."
He said previous attempts to make changes to the laws around lobbying had often butted up against other factors.
"Trying to do things that target lobbying can inadvertently target other people seeking to democratically participate in the process of governing, and we don't want to have a chilling effect on that either," he said.
However, he did not rule out further attempts in future.
"I certainly wouldn't take things off the table."
National Party leader Christopher Luxon earlier said he thought more regulation of lobbyists was needed, including on things like stand-down periods for moving between political and lobbying jobs, rules for maintaining independence, and making declarations.
"We should also get clear about why government agencies are using lobbying firms themselves as we've seen with Pharmac and others and let's get really clear about declarations of who is working for who," he said.
"We're a small country, we know a lot of people, we move [into] different careers, through different sectors and different industries, I think it probably is a good time to take some stock."
He said he had been talking about options with his Public Service and Justice spokespeople, Simeon Brown and Paul Goldsmith.