Over 12,000 foreign fighters in Syria

A leading expert on terrorism matters believes more than 12,000 foreigners have gone to Syria to fight, with around 25 per cent of those from the West.

A leading expert on terrorism says more than 12,000 foreigners have gone to fight in Syria. (AAP)

A leading expert on terrorism says more than 12,000 foreigners from 74 countries have gone to fight in Syria.

Professor Peter Neumann says 60-70 per cent of those are from other Middle Eastern countries and about 20-25 per cent from Western nations.

Neumann directs the International Centre for the Study of Radicalisation at King's College London.

He says the Syrian conflict has sparked the most significant mobilisation of foreign fighters since the 1980s war in Afghanistan.

The Afghan conflict produced al-Qaeda and the Syrian conflict was now forging new networks that would carry out terrorist attacks, he said.

Neumann has been consulting the UN Security Council ahead of its September 24 summit meeting, chaired by President Barack Obama, on foreign terrorist fighters and the threat they pose.