Iranian Foreign Minister Mohammad Javad Zarif has defended his country's human rights record during his trade-related visit to New Zealand.
The government is looking to "refresh" New Zealand's relationship with Iran - after long-running economic sanctions were lifted this year.
The visit was the first by an Iranian Foreign Minister in more than 10 years, but some groups were sounding a warning about developing closer ties.
Along with other countries, New Zealand lifted sanctions imposed in 2006 last month after Iran agreed to roll back its nuclear activities.
Amnesty International New Zealand executive director Grant Bayldon said Iran's human rights record should be questioned by New Zealand as the two countries moved to a closer trading relationship.
"In Iran right now, people are still being arrested for things that shouldn't be crimes at all," he said.
"Within the justice system there, people are routinely tortured into confessions, convicted in sham trials - and sentences include amputations, blindings, floggings and executions."
He said New Zealand could not just ignore it.
"So really this is a test for the New Zealand government, and the test is whether it will just represent New Zealand's trade interests or whether it will also represent the values that New Zealanders hold dear - and of course human rights needs to be right up there."
Prime Minister John Key said human rights, and the death penalty in particular, were raised during his discussion with Dr Zarif.
"We had quite a long talk about why so many people were being put to death. He reaffirmed that that's in relation to drug trafficking.
"I asked him about the nationality of the individuals involved, he said they were almost always Iranians. They're involved in the trafficking of drugs which I think are largely poppies that are grown in Afghanistan.
"And he said that they're trying to send the strongest message possible that Iran shouldn't be used as through-port for drugs that get ultimately sent into Europe."
Mr Key also said New Zealand traded with many countries that had a death penalty, despite long-standing opposition to that policy.
During a speech to the Institute of International Affairs at Parliament, Dr Zarif defended Iran's record, but he acknowledged it could do better.
"I never claimed that we do not need improvement.
"Actually, as someone who taught human rights when it was not fashionable to teach human rights, in Iran, I believe that we can make a lot of improvement and so does the President [Hassan Rouhani].
"That's why the president has promised, has campaigned on a platform of a charter of citizens' rights which he will be presenting to the general public."
Dr Zarif was due to arrive in Australia today, where he was expected to meet with Foreign Minister Julie Bishop and discuss a deal under which Iranian asylum seekers could be sent back to Iran.
Dr Zarif said his country would not take anyone back to Iran against their will unless they were wanted for criminal acts.
He also gave assurances that none who returned would be mistreated, prosecuted, or punished for fleeing Iran in the first place.