PHNOM PENH - CAMBODIAN Prime Minister Hun Sen on Wednesday warned critics that they risked facing legal action if they called the country a 'dictatorial regime'.

'Be careful with the language of 'dictatorial regime'. Be careful, (or) one day legal action will be used,' Mr Hun Sen said during a graduation ceremony in the capital Phnom Penh.

The premier's warning appeared to be aimed at those who allege senior Cambodian officials have over the past several months used defamation lawsuits against critics to impede freedom of expression in the country.

'This is a constitutional monarchy... Don't curse it as a dictatorial regime - be careful!' Mr Hun Sen said.