Prime Minister Jacinda Ardern lashes Australia over treatment of Manus Island refugees

Prime Minister Jacinda Ardern has blasted Australia's handling of the refugee crisis on Manus Island as unacceptable as she seeks another meeting with Malcolm Turnbull on the issue.

Ardern has continued to push New Zealand's offer to accept 150 refugees and asylum seekers from Australia's offshore detention centres since her first face- to-face meeting with her Australian counterpart in Sydney a week ago.

She wants a more substantive conversation when both leaders reach the Philippines for the East Asia Summit this week.

"We made the offer because we saw a great need. No matter what label you put on it there is absolute need and there is harm being done," she said on Saturday night (Sunday morning NZ time).

"I see the human face of this and I see the need and the role New Zealand needs to play. I think it's clear that we don't see what's happening there as acceptable, that's why the offer's there."

It's her strongest statement to date against the unfolding crisis.

There are 400 refugees and asylum seekers who have barricaded themselves inside the mothballed detention centre, fearing for their safety if they leave.

The United Nations has raised concerns over reported instances of assault, sexual abuse, self harm and suspicious deaths.

Ardern hasn't revealed the content of the talks with Turnbull, but said the fact they are continuing proved the urgency of the situation.

New Zealand won't pursue a deal directly with Papua New Guinea, despite Foreign Minister Winston Peters spotted holding talks with PNG's Prime Minister Peter O'Neill.

Ardern said it was faster to organise the logistics of any deal with Australia.

"It continues to be the easiest option is to go through Australia given the screening that's already occurred of those refugees ... I'm interested in the fastest route," she said.

Peters has made it clear New Zealand's offer also includes refugees and asylum seekers in Australian detention centres in Nauru.