The levels of jihadist activity in Indonesia are the highest they have been in a decade and foreigners are a key target, according to terrorism expert Sidney Jones.

Speaking at Murdoch University's Asia Research Centre in Perth, Ms Jones said it was likely there would be more violence in the short term, as Indonesia's many groups — inspired by Islamic State (IS) — switched their focus to domestic attacks after finding it difficult to get to Syria.

"I think for the last two and half years or so, we've seen a focus of the groups committed to violence with getting to Syria," she said.

"All of their energies have been on how you emigrate and join ISIS in Syria.

"Now it's become harder to get to Syria — the Turkish border has got more tight, the Indonesians have gotten more vigilant, there's been more prosecutions.

"The message from leading extremist groups is if you can't get to Syria, wage war at home".

The head of the Jakarta-based Institute for Policy Analysis of Conflict, Ms Jones said Indonesian jihadist groups were taking their inspiration and often, orders, from Islamic State operatives in Syria.

"We have more activity among jihadi groups than in any time in the last 10 years," she said.

The bombings in Jakarta in January, which killed eight people, were an example of IS-inspired terrorism.

"That was also clearly sparked by several men in Syria vying for leadership and recognition by the ISIS central leadership, so it's been a kind of one-upmanship," Ms Jones said.

"We had the January attacks because these guys wanted to do a version of Paris in Jakarta."

But she said the bombings were "unprofessional" and "kind of pathetic" because the extremist groups lacked the money and training for a sophisticated attack.

'Americans, Australians - anyone who's involved'

While Indonesian groups might not have the capability to pull off a large-scale attack like the 2002 Bali bombings or the 2004 Australian embassy bombing in Jakarta, Ms Jones said it did not mean they were unable to commit acts of terrorism.

"When you think of terrorism attacks, you can't just think of targeting a Starbucks, targeting a hotel," she said.

"You have to think these days of somebody coming up with a knife and going after a foreigner."

While police are the number one focus of Indonesian extremists, foreigners — particularly nations involved in the US-led coalition against IS — remain a key target, Ms Jones said.

"It includes anybody from the coalition — that means Americans, Australians - anyone who's involved," she said.

"Unfortunately, it tends to translate into anyone who's white."

In February, the Department of Foreign Affairs and Trade warned that terrorists could be in the "advanced stages" of planning attacks in Indonesia.

It is advising travellers to be vigilant when travelling throughout the country, including tourist spots like Bali.