Mr Abhisit, 44, was nominated premier in an emergency parliament session on Monday, two weeks after a court dissolved the ruling party loyal to ousted premier Thaksin Shinawatra and after six months of political turmoil.

State-run television showed footage of the 81-year-old constitutional monarch signing the decree and handing it to the speaker of the house, Chai Chidchob.

The document will first go to parliament to be logged, before being ferried to the Democrat Party headquarters, where the parliament secretary will read the royal command to Abhisit.

Security was tight at the party headquarters, following violent protests outside parliament on Monday by supporters of the old government.

About 300 policemen including anti-riot officers stood guard, while a bomb disposal team with two sniffer dogs checked the compound.

British-born Mr Abhisit will later address the nation to outline his policies, with expectations high after months of protests against the previous government that peaked with the occupation of Bangkok's airport late last month.

The sieges only ended after a court on Dec 2 dissolved the Thaksin-linked People Power Party and removed then-premier Somchai Wongsawat from office.

Mr Abhisit has said he will name his new cabinet later on Wednesday or on Thursday. -- AFP

Read also:
Cabinet will be competent