In the wake of the crisis in Aleppo, the Greens are once again calling for New Zealand to take in more emergency refugees.

Tens of thousands of people are still trapped in the besieged city after the evacuation was brought to a halt.

And the United Nations is warning 2700 children are trapped alone in the city.

Green Party Immigration spokeswoman Denise Roache said New Zealand has the ability to reach out to these people.

"When our community forced the government to shift from the refugee quota that we had at 750 to an increase to 1000, they actually said there is extra capacity for emergency situations," she said.

"If you look at the media that's coming out of Aleppo, I can't think of a worse emergency where we need to act."