They included Australia, Britain, Canada, New Zealand and the United States. They issued travel advisories to their citizens in Bangkok to stay at home and avoid moving about the city.

They also warned that more attacks were possible in coming days.

New Zealand's foreign ministry issued a travel warning about Bangkok on Monday, saying there was some risk to security and recommending tourists to exercise "a high degree of caution" in Bangkok following the New Year's Eve bombings.

The ministry advised New Zealanders in Bangkok to avoid unnecessary travel within the city and said terrorist attacks may also occur elsewhere in Thailand, including in tourist areas.

"New Zealanders should therefore exercise a high degree of personal security awareness about possible terrorist action in Thailand generally, particularly in public and commercial areas, including landmark places known to be frequented by foreigners, public transport facilities, hotels, bars and shopping areas," the ministry said on its travel safety website.

It said there was no evidence to suggest New Zealand citizens would become targets, but said there was a danger of bystanders inadvertently getting caught up in unpredictable acts of violence.

The ministry continued to warn of a "high risk" to security in Narathiwat, Yala, Pattani and Songkhla because of ongoing violence due to insurgency and recommended against all non-essential travel there.

Australia's Department of Foreign Affairs and Trade also issued a travel advisory in its website, saying "There is a possibility of further attacks in coming days. "Australians are urged to avoid unnecessary travel in Bangkok."

Earlier United Kingdom's the Foreign Office warned British travellers not to travel around Bangkok "unless absolutely necessary."

Agencies