Reuters/Sydney

Australia's anti-money laundering agency says reports of suspected "terrorism-financing" tripled in the past year, with over A$50 million ($35.92 million) which could be used to support militants being investigated.

The financial intelligence agency, AUSTRAC, said in its annual report released this week that it had recorded a trebling of "suspicious matter reports" that could be linked to funding of militant groups. It recorded up to 367 reported cases in 2014-15 from 118 a year earlier.

"The volume of terrorism financing in Australia is linked to the number of Australians travelling to join terrorist groups in Syria and Iraq," the report said.

Roughly A$53 million dollars, A$11 million in cash, was reported as suspicious to the agency. The funds may have been intended to cover a variety of activities, including paying family members who died in operations, AUSTRAC said.

Australia is on high alert for attacks by radicalised Muslims or by home-grown militants returning from fighting in the Middle East, having raised its threat level to "high" and unleashed a series of high-profile raids in major cities.

Security analysts have put the number of foreign fighters in Iraq and Syria, travelling from scores of countries around the world, in the thousands. AUSTRAC said in the report that it was monitoring around 100 people.

About 120 Australians are believed to be fighting with Islamic State and other militant groups in Iraq and Syria, with several believed by intelligence agencies to hold leadership positions in Islamic State.

Australian citizens now face up to a decade in prison for travel to overseas areas declared off-limits and the government has worked to halt the flow of funds overseas.

Canberra last year shut a money transfer business linked to the family of suspected Australian Islamic State fighter Khaled Sharrouf on suspicions it transferred up to A$20 million to foreign militants. Sharrouf was killed in Iraq earlier this year.