Iran has refused a deal to take back Iranian asylum seekers, who Australia wants to deport, but has shaken on an intelligence sharing deal that would advance mutual benefits in the fight against Islamic State.

Foreign Minister Julie Bishop went to Tehran with the asylum seeker deal as her main stated agenda item, but emerged empty handed on that point.

But Australia will tap into Iran’s “sophisticated” and broad intelligence network to track foreign fighters under an unprecedented spy co-operation deal.

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Ms Bishop brokered what she described as an informal arrangement following meetings at the weekend.

Iran had a sophisticated intelligence network and operatives in places where Australia didn’t.

“There is a lot of information they’ve been gathering,” she said.

“It was an informal arrangement whereby we would share intelligence on Australians who are taking part,” she said on Sky News.

Sky News reported that about 150 Australians are fighting with Islamic State and about 30 Australians have been killed amid the militia.

However, Ms Bishop would not detail what information Australia would hand over to the once-pariah state, but it would be whatever was of interest to the Rouhani administration in their “common purpose” of defeating Islamic State.

“Then that’s an appropriate exchange,” Ms Bishop said.

On Monday Prime Minister Tony Abbott used an Anzac commemoration with New Zealand Prime Minister John Key in Wellington to flag a push for more policing on the Turkish border to stop Australians joining Islamic State in Syria and Iraq.

“Australians who have gone to fight with the death cult have mostly gone through Turkey.”

“I will be talking with the Turkish leadership about what can be done to better police that border,” Sky News reported.

“It is absolutely critical that as far as humanly possible, we stop gullible, impressionable young Australians from going to places where they could very easily be killed or they could get caught up in something that is in no one’s interests,” the New Zealand Herald reported.

Despite success on tactical matters, Ms Bishop failed in immigration talks with Iran refusing to accept its asylum seekers deported forcibly on the grounds it violates human rights.

But she has managed to win agreement for their voluntary return, and the two countries have agreed to keep diplomatic lines open on immigration co-operation.

Immigration Minister Peter Dutton has warned he will not fold on denying asylum seeker boat arrivals settlement.

The government has been specific about plans not to allow asylum seekers who came by boat to settle in Australia and would return people to their country of origin where possible, he said.

— with AAP