Winston Peters says New Zealand should tell some Syrian refugee men to go back and fight for their country's freedom.

The New Zealand First leader, a long-time immigration critic, backs the Government's emergency intake of 600 refugees from the war torn country, but with a controversial condition.

"I think we can do better, but we can't while we've got mass immigration," Mr Peters said.

"If we are going to do it, let's take the women and children and tell some of the men to go back and fight for the country's freedom like we are."

While Mr Peter's idea is unlikely to fly, Syrians coming to New Zealand will be extensively checked beyond routine United Nations' assessments.

"There are some filtering processes including people with polygamous marriages or those that have been directly involved in the conflict. Those people will be declined," says Michael Woodhouse, Immigration Minister.

The Government is sticking with its emergency plan to take in 750 Syrian refugees over the next two-and-a-half years.

A push by the Greens to increase New Zealand's total refugee quota from 750 a year to at least 1,000 failed.

Opposition parties challenged the Government in Parliament today over whether it really is doing enough.

Greens co-leader James Shaw asked Mr Woodhouse why he voted down the Greens' bill to increase the quota to 750 and stop public consultation on the refugee quota.

Mr Woodhouse responded that of the 193 UN countries, only 22 of them take quota refugees and "New Zealand ranks about sixth or seventh on that list".