Australia warns more terror attacks 'likely' in Sri Lanka

Australia on Thursday warned more terror attacks were "likely" in Sri Lanka, cautioning citizens against visiting the island nation following the Easter Sunday bombing that claimed 253 lives.

"Terrorists are likely to carry out further attacks in Sri Lanka," the foreign ministry warned in its latest travel advice.

"Attacks could be indiscriminate, including in places visited by foreigners," it said.

Canberra advised Australians to "reconsider your need to travel to Sri Lanka", following similar warnings from Britain, the Netherlands and the United States since the April 21 bombings.

The US State Department has warned that terrorist groups "continue plotting" possible attacks, with targets including tourist locations, places of worship and airports.

An Australian mother and her 10-year-old daughter were among those killed in the series of bomb blasts that targeted tourists and Christian worshippers.

Prime Minister Scott Morrison said Australian counter-terrorism police would assist Sri Lankan authorities with their investigation.

Tensions remain high in Sri Lanka and a curfew has been put in place across the island, with authorities still in a desperate search for suspects.

Authorities on Thursday revised down the death toll by more than 100 to 253, admitting some of the badly mutilated bodies had been erroneously double-counted.