BANGKOK (AFP) - Thai opposition protesters were preparing Friday to relaunch their campaign to overthrow the government after a temporary truce in the strife-hit capital for the birthday of the country's revered king.

Despite a call by the ailing monarch for "stability and security" in his birthday speech, the demonstrators have vowed to step up their rallies after the lull in tensions, which follows violence that left five people dead and more than 200 injured.

Protesters have no immediate plans for action on Friday and will await an "important speech" in the evening from their leader Suthep Thaugsuban about their next move, said Mr Akanat Promphan, a spokesman for the demonstrators.

The kingdom remains on edge following several days of street clashes between police using tear gas, water cannon and rubber bullets against rock-throwing demonstrators seeking to overthrow Prime Minister Yingluck Shinawatra and curb the political influence of her brother Thaksin.

With fresh unrest looming, Ms Yingluck has cancelled two planned trips overseas next week to Russia and to the opening ceremony of the Southeast Asian Games in Myanmar, her office said.

The protesters, a mix of royalists, middle class and other Thaksin opponents - sometimes numbering in their tens of thousands - want to suspend the country's democracy in favour of an unelected "people's council".

Mr Suthep, a former deputy premier who now faces an arrest warrant for insurrection, has pledged to rid Thailand of what he calls the "Thaksin regime".

Demonstrators and police in Bangkok have observed a temporary truce since Wednesday for the 86th birthday of King Bhumibol Adulyadej, who is treated as a near-deity by many Thais.

Any political action or violence during the public holiday would have been seen as a serious sign of disrespect.