UK warns Aust of increased terror threats

British Foreign Secretary Philip Hammond has warned of more violent extremism, and the need to deal with terror groups such as Islamic State wherever they emerge.

Speaking following high-level security talks in Sydney, Mr Hammond said the UK and Australia were involved in a generational struggle, but were also "determined to remain unflinching in our resolve to stand firm and to confront this poisonous ideology".

"Although the focus at the moment is on Iraq and Syria, we should be prepared to see manifestations of extremist Islamism ... popping up all over the place, and we've got to be prepared to deal with them wherever they emerge, wherever they show their head," he said.

Russian aggression in Ukraine also featured in Monday's discussions.

But the growing threat posed by Islamic State and its ability to attract foreign fighters dominated the annual Australia-United Kingdom Ministerial security talks.

Earlier Mr Hammond, along with British Defence Secretary Michael Fallon, visited Martin Place and signed a condolence book for victims of the Lindt cafe siege.

"My visit to the Lindt cafe this morning has really brought home to me the fact that no city anywhere in the world, not London, not Paris nor Sydney, is immune from the threat of global terrorism," Mr Hammond said.

Australian authorities have cancelled the passports of around 80 citizens suspected of planning to commit a terrorist act or engage in politically motivated violence overseas.

Attorney-General George Brandis recently said the number of Australian foreign fighters had increased from an estimated 70 last year, to about 90.

Foreign Minister Julie Bishop said the UK and Australia were dealing with the emerging threat of a form of terrorism "that is more complicated, more diversified, more dangerous than ever before".

The meeting included discussions on the Five Eyes project - the spy network that includes the US, Canada, Australia, UK and New Zealand - and the need to continue to share information and intelligence.

Ms Bishop and Mr Hammond also signed a Memorandum of Understanding to formalise the sharing of diplomatic resources in times of emergencies, such as when flight MH17 was shot down over Ukraine.

Defence procurement and potential co-operation on shipbuilding were also discussed.