Foreign Minister Julie Bishop says the number of Australian terror fighters overseas has doubled in the last 12 months, despite efforts to cancel passports and increase intelligence operations.

Ms Bishop, speaking from the UN General Assembly in New York on Monday morning (AEST), said there was about 120 Australians currently in Iraq and Syria supporting Daesh and other terrorist groups.

She said the government had been proactive in cancelling passports and instigating interventions with intelligence agencies.

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Julie Bishop is in New York for a UN summit. Photo: Getty

“I found the number I reported from here [UN General Assembly] 12 month ago has doubled,” Ms Bishop said.

“The numbers are increasing but we continue to expand the trajectory of our efforts.”

Ms Bishop is in the US for the summit where she will meet with other world leaders and officials to discuss global issues.

Combating climate change and terrorism, in particular war-torn Syria, is on top of the agenda.

Meanwhile, at a counter-terrorism forum hosted by US Secretary of State John Kerry on the sidelines of the UN summit, Ms Bishop aired concerns about the threat by prisoners convicted of terror charges who were being released from jails across Asia.

She said hundreds of convicted terrorists were to be released from jails in the Asian region and they could pose great threat if not rehabilitated.

“A significant number of prisoners in Indonesian prisons who have been convicted of terrorist-related activities will be released. It runs to the hundreds,”Ms Bishop said.

She said there was concern those prisoners were radicalising fellow inmates and spreading extremist ideology.

On Sunday, Ms Bishop spoke at another sideline event, the USAID forum, about foreign aid.

She said governments were no longer the main drivers of foreign aid, something the Federal Government had recently been criticised for reducing.

She said economic growth had lifted one billion people out of poverty, which was why Australia was adopting “economic diplomacy” as the cornerstone of its foreign policy.

Ms Bishop announced Australia would provide $3.5 million to the Asian Development Bank to help small enterprises in developing nations.

She later spoke to the UN summit about how Australia planned to meet sustainable development goals.

– with AAP/ABC