Australia is poised to send extra troops to Iraq to train its security forces in the fight against Islamic State.

The New Zealand government yesterday announced it would send 143 soldiers as part of a 400-strong joint Australia-NZ training team, subject to agreement from Canberra.

Prime Minister Tony Abbott told reporters in Sydney today that he had been talking to the Iraqi government about what more Australia could do.

“Obviously that includes the New Zealanders, about what more we can do to help the Iraqi security forces and I’ll have more to say in the next day or so,” he said.

Defence force chief Mark Binskin earlier told a Senate estimates hearing he and his NZ counterpart had developed options which had been put to both governments.

“The government of Australia has yet to make a final decision,” he said.

Foreign Minister Julie Bishop says the national security committee of cabinet is reviewing the commitment.

“We have had our presence in Iraq under constant review to ensure that we’re achieving the best outcomes,” she said.

Mr Abbott travels to Auckland for meetings with NZ Prime Minister John Key on Friday and Saturday.

Labor says it has not been briefed about the new deployment, but Opposition Leader Bill Shorten vowed to continue providing constructive support.

Australia now has some 200 special forces operating inside Iraq advising and helping Iraqi security forces.

Six Super Hornets, a KC-30 airborne refuelling aircraft and a Wedgetail airborne control aircraft continue to conduct operations.

Australian combat aircraft have dropped some 200 precision guided bombs.

Air Chief Marshal Binskin told the Senate hearing IS, or Daesh, had suffered significantly from coalition air power.

They had lost some 2000 fighters, including foreigners around Kobani in Syria.

They no longer openly travelled in large groups or displayed the IS flag on vehicles.

Their senior leaders did not wear uniforms.

“They still do try and set up checkpoints but that makes them quite obvious and the checkpoint soon disappears in a bit of dust,” Air Chief Marshal Binskin said.

Defence chiefs have dismissed a report that Mr Abbott last November suggested a unilateral Australian deployment of 3500 troops into Iraq to fight IS.

Defence department secretary Dennis Richardson told the estimates hearing the prime minister had not raised the idea with Defence formally or informally, directly or indirectly.

“We have checked with a whole range of people in the ADF who might be described as leading defence planners and we all simply scratch our head,” he said.

Mr Abbott has dismissed as “fanciful” reports he floated the idea, a description supported by Air Chief Marshal Binskin.