Costa Rica refugee plan department's idea

The immigration department devised the proposal for Australia to take refugees from Central America as part of a US-led program.

Prime Minister Malcolm Turnbull made the announcement during a speech to President Barack Obama's invitation-only, high-level summit on refugees and migration in New York in September.

Immigration department officials told a Senate estimates hearing on Monday, "small numbers" of refugees would be resettled and no date had been set for arrivals so far.

The refugees are living at a centre in Costa Rica.

Discussions between Australia and the US had spanned all year.

Officials later revealed they were alerted to the opportunity of taking Central American refugees from a US government department press release.

They declined to say whether Australia had discussed the prospects of a people swap of refugees and asylum seekers on Manus Island or Nauru in exchange for taking Central American refugees.