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.