SYDNEY (AFP) - Australia on Thursday passed a law criminalising travel to terror hotspots, a tough counter-terrorism measure aimed at stopping militants from going to Iraq and Syria to fight.

The Australian government has been increasingly concerned about the flow of foreign fighters to the Middle East to join militant groups such as the Islamic State in Iraq and Syria, with 70 Australians believed to have already made the journey.

The Counter-Terrorism Legislation Amendment (Foreign Fighters) includes measures that make it an offence to enter a "declared area" where a terrorist organisation is engaging in hostile activity, without a valid reason. The offence carries a maximum penalty of 10 years in prison.

"The Foreign Fighters Bill that has passed the Parliament today will mean, first of all, that it is easier to secure convictions against Australians who have been fighting with terrorist groups overseas," Prime Minister Tony Abbott told Parliament on Thursday. "It will mean that it is easier to monitor potential terrorists here, and it will also mean... that it is easier to prosecute the preachers of hate who create the potential terrorists."

Mr Abbott told Parliament about 100 Australians were supporting militants who had travelled to the Middle East to fight with recruitment and funding from home.

Some 20 militants who fought with terrorist groups in the region had also returned to Australia, Mr Abbott added.

"The best way to deal with returning foreign fighters is to stop them leaving in the first place... and I'm able to inform the House that some 70 Australian passports have been cancelled to stop terrorists or potential terrorists from travelling."

The new law, which was passed by the Lower House of Representatives on Thursday with bipartisan support, came as the Labor opposition raised concerns that another national security measure passed in September could see journalists jailed for up to 10 years.

Attorney-General George Brandis refuted the concerns, saying that the legislation was instead "intended to deal with a Snowden-type situation".

Documents leaked by United States intelligence fugitive Edward Snowden included reports in November that Australian spies tried to tap the phones of former Indonesian president Susilo Bambang Yudhoyono and his inner circle, damaging relations between the two countries.