National Party leader Christopher Luxon says a member of his staff was told about the red flags around candidate Sam Uffindell during the campaign for the Tauranga by-election.
He said in error, it was not passed on to him, but if it had been he would have passed that information on to voters.
Speaking to reporters before heading into Parliament this afternoon, Luxon repeated his stance the incident should have been outlined to the public.
"This should have been in the public domain for the public to be aware of and there's a number of ways that could have been achieved. Unfortunately I wasn't informed of that and as a consequence it didn't get out to the public," Luxon said.
National MP and Uffindell's campaign chair Todd McClay yesterday said it had not been his role as campaign chair to speak directly to the party leader and inform him about things that happened in the selection process.
Luxon today defended McClay, who was on Uffindell's selection panel, saying he had found out new information.
"Todd McClay did an outstanding job as campaign chair, and what I'd say to you is Todd McClay's done nothing wrong because he did in fact inform my staff but my staff did not pass that through to me.
"That is regrettable and I get that's difficult, but I can tell you Todd didn't do anything wrong."
He said he would not get into the details of which staffer.
"Essentially what Todd did was that, in that campaign - over some time during that campaign - he informed my staff. That wasn't passed through to me and that is regrettable, and it's a mistake but it is where we are and we're now focused on the investigation.
"I think it was a genuine mistake and I appreciate that it's a mistake and it's regrettable and it's not ideal. We've had that conversation about expectations but I have to say, I trust my staff."
He also defended the record of the party's new president, Sylvia Wood.
"I think Sylvia's done an excellent job. She reacted immediately to the red flag of Sam's application and then she put in place reference checking along the way and we've explored everything as much as we can."
He said he was reserving his judgement on whether he still considered Uffindell a good candidate with high integrity until after the findings of the independent investigation into the new allegations.
He had sought assurances from Uffindell there were no further issues to be raised, he said.
"I have since the beginning of the issues of this week, and that's why I was informed previously that the King's College incidents was the most serious events that we were aware of. New allegations emerged last night, and when you look at them they are pretty serious and concerning."
"I want it to be a safe, independent vehicle and mechanic by which the complainant can really put their side of the story given the nature of these complaints. Equally, given Sam is strongly refuting aspects of the allegations, I need to follow good process."
Prime Minsiter Jacinda Ardern would not speak about the National Party's concerns, but said Labour had worked towards better representation in Parliament of the communities in New Zealand, and a cross-section of talents, skills and backgrounds.
"We have processes to ensure to the best of our abilities that when we're working through candidate selection that we're aware of issues and ensure that, again, to the best of our abilities, we're representing communities but also role-modelling the kinds of behaviours that we would like to see in Parliament."
"Any process that you design, just like in any workplace, is not necessarily going to be perfect but we've certainly worked hard to try and improve those kinds of systems."