Some of the Pacific's foreign ministers are expected to raise concerns over Nauru's crackdown on dissent when they meet on Thursday and Friday at the Pacific Islands Forum foreign ministers meeting in Sydney.

Nauruan president Baron Waqa is expected to attend the event, which will primarily focus on the Pacific's disaster preparedness.

But with ongoing issues in relation to law and order and human rights, the situation on Nauru will also be raised.

Protests outside the nation's parliament in mid-June led to the arrest of three opposition MPs, two of whom are still in custody, and one other being prevented from leaving the country to be with his family in New Zealand.

The Nauru government says it is upholding the law, and maintains opposition MPs — five of which have been barred from taking their seats in parliament since mid-2014 — are engaging in criminal activities and spreading lies in foreign media outlets like the ABC.

Sorry, this audio has expired Secretary General says Pacific Islands Forum has a mechanism to intervene in Nauru ( Bruce Hill )

In a statement on Tuesday, New Zealand's foreign minister said he would have a one-on-one meeting with Nauru's president.

"New Zealand is taking the reports coming out of Nauru very seriously and this meeting is an opportunity to pass on our concerns and discuss our contribution to the justice sector in light of recent events," Murray McCully said.

In a statement on Wednesday, Nauru's government said Mr Waqa was willing to meet with Mr McCully in Sydney.

However, justice minister David Adeang accused some New Zealand MPs of "making rash comments without understanding the facts".

"Contrary to reports in some sections of the media, there is certainly no breakdown in democracy or any other turmoil in Nauru," Mr Adeang said in the statement.

"We are merely upholding the rule of law and those who break the rules will be arrested.

"It is true, several Opposition MPs are before the courts because of their alleged involvement in a violent parliament riot last month and they will be provided with a fair trial."

Mr Adeang said there had been "positive discussions" between Mr Waqa and Foreign Minister Julie Bishop earlier this week, but did not elaborate.

The secretary-general of the Pacific Islands Forum, Dame Meg Taylor, told Pacific Beat "there's been concern expressed by other member states about what is going in Nauru".

Sorry, this audio has expired Australia lets NZ take the lead on Nauru rule of law issue ( Bruce Hill )

"When the issues in Nauru started to blow up, we kept in touch particularly with officials as to what was happening," she said.

Dame Meg said she immediately got in contact with the current chair of the Pacific Islands Forum, Palau's president Tommy Remengesau Jr, to engage in "dialogue at a leadership level".

She said Nauru was entitled to sort out its own problems before any intervention is considered.

"It's the timing of any intervention and how we go about that, and making sure that it's not interfering, when a country has every right to sort itself out without being told 'you can't do this, you can't do that'," she said.

"We have the Biketawa Declaration that provides the instrument so that other countries can get involved," she added, speaking of the forum's guiding principles for good governance and courses of action for a regional response to crises.

The Biketawa Declaration was applied when the Solomon Islands parliament voted unanimously for the regional intervention force RAMSI to assist in violent troubles there for 10 years from 2003.

Discussions, however, are still very much in their infancy.

"There will be discussions between different ministers with the president of Nauru," said Dame Meg.

Director of the Melanesia program at the Lowy Institute, Jenny Hayward-Jones, said New Zealand was well placed to raise rule of law concerns.

"New Zealand aid does fund the legal sector there, and therefore I guess does feel more responsible for things going wrong in the legal sector and the breaches of the rule of law," she said.

"Australia does have some leverage," she said of Australia's $26 million aid contribution to Nauru, plus the hundreds of millions in funding its regional processing centre and refugee resettlement on Nauru, "but perhaps it's just being cautious about how it uses that leverage at this stage."