The foreign minister Marise Payne says she has written to her Iraqi counterpart to call for the release of detained Australian citizen Robert Pether.

Pether has been held without charge in Baghdad for roughly 50 days, after the engineer travelled to Iraq to resume work on the construction of the country’s new central bank headquarters. The project was mired in a contractual dispute.

When he arrived for a meeting with representatives of the Central Bank of Iraq, Pether was arrested. Payne told Perth radio on Thursday that she had taken the matter up with Iraqi foreign minister Fuad Hussein.

“It is a very distressing time both for [Pether] and his family. So, we’re strongly advocating his case, both for his rights and his welfare to the Iraqi authorities. What I asked the Foreign Minister is to seek his release if there is no clear basis to detain him, as you say, and no charges have been laid. And we are continuing to seek advice from the Iraqi authorities on what charges, or whether charges, will indeed be brought against him.”

Payne said Australian diplomats were “closely engaged with Iraqi authorities” and were seeking clarity about the nature of the complaint against Pether.

And if it is indeed a civil matter, a contractual matter, then we would seek for it to be treated in that way. We don’t interfere in the legal systems of other countries, as we would say they should not interfere in ours. But we do advocate strongly for Australians who are impacted in circumstances such as this. And it is vital that we have access to those governments and access to their systems to advocate in that way. And in this case, we definitely do.”

New Zealand has extended its pause of quarantine-free travel with Victoria for seven more days in response to the outbreak in Melbourne.

The government has also directed all people who have travelled from the greater Melbourne area to New Zealand since 20 May to self-isolate immediately and get tested.

They are required to stay self-isolating until they receive a negative test result. That constitutes a legal directive, not just advice from government – it is an offence not to comply with the New Zealand order.

Officials estimate that about 5,000 people will need to be tested and self-isolate.

Covid-19 response minister Chris Hipkins said New Zealanders in the greater Melbourne area should “hunker down, follow the rules”.

The pause in quarantine-free travel between Victoria and New Zealand is now due to end at 7.59pm on 4 June but remains subject to review.

This is the first extended pause in travel between New Zealand and Australia since the travel bubble opened.