Australia on Thursday warned that terrorists might be in the "advanced stages of preparing attacks" in Indonesia and advised travellers to take precautions, just days after a similar warning about neighbouring Malaysia.

"Recent indications suggest that terrorists may be in the advanced stages of preparing attacks in Indonesia," the Department of Foreign Affairs and Trade (DFAT) said in an updated travel advisory.

"We advise you to exercise a high degree of caution in Indonesia, including Jakarta, Bali and Lombok, due to the high threat of terrorist attack."

The advisory did not raise the overall threat level, which is at "exercise a high degree of caution", and noted that the department continued to "receive information that indicates that terrorists may be planning attacks in Indonesia, which could take place anywhere at any time".

It said travellers should be particularly careful when in places that have low levels of security and while at possible known terrorist targets, listing previous attack sites such as nightclubs, bars, cafes, restaurants, international hotels, airports and places of worship.

"The Indonesian government has recently increased security across Indonesia, which underscores the ongoing high threat of a terrorist attack," it added.

However, a spokesman for Indonesia's national police said authorities had not seen any indications of an imminent attack.

"We have not found anything worrying," spokesman Agus Rianto told AFP. "At the moment, Indonesia is safe."

DFAT on Sunday warned of possible attacks in and around the Malaysian capital Kuala Lumpur, that they could be indiscriminate and may target Western interests or locations frequented by Westerners.

Indonesian police on Friday arrested dozens of suspected Islamic extremists on Java island, but it was not clear if they were linked to gun and suicide attacks in Jakarta last month that left four civilians and four assailants dead.

The Jakarta attacks were claimed by the Islamic State group, which has provided a potent new rallying cry for Islamic extremists in Indonesia, the world's most populous Muslim-majority country.

Indonesia suffered several major bomb attacks by Islamic radicals between 2000 and 2009, but a subsequent crackdown weakened the most dangerous networks.