Thailand on Wednesday said it was boosting security ahead of an incendiary charter amendment case that could lead to the dissolution of the ruling party, with judges given special police protection.
Deputy Prime Minister Yutthasak Sasiprapa warned that Friday's verdict, which threatens to rip open the kingdom's bitter political divisions, "could trigger violence", but said there was no specific threat of unrest.
Nearly 2,000 police officers are to be deployed around the Constitutional Court as it prepares to rule over claims that plans by Thai premier Yingluck Shinawatra's party to amend the constitution are a threat to the deeply-revered monarchy.
A verdict against the ruling party could lead to its dissolution, risking fresh conflict in a nation that has been racked by bloody street rallies since huge protests against Yingluck's brother Thaksin helped topple the tycoon from power in 2006.
A small anti-Thaksin rally is expected in front of the court on Friday, but rival "Red Shirts" -- longterm supporters of the fugitive former premier -- are not expected on the streets before the verdict.
Deputy national police chief General Adul Saengsingkaeo said 13 companies of officers would be deployed on Friday at the Court, with Special Branch and Bangkok Metropolitan police assigned to provide security for the judges.
Yutthasak said he hoped the situation would not get "out of hand", but that the military were prepared to step in if needed.
"All Constitutional Court judges will be protected by military officers and on standby for evacuation if the situation deteriorates," he told reporters at Government House in Bangkok.
Two pro-Thaksin premiers were forced from office in 2008 in judicial rulings, making way for the Democrats to take power in a parliamentary vote.
Yingluck's Puea Thai party swept to power last year on a wave of Thaksin support following deadly 2010 Red Shirt street protests, promising to amend the constitution, which was drawn up under the post-coup junta in 2007.
A dissolution of Puea Thai -- which denies any intent to undermine the monarchy -- would not necessitate Yingluck's departure, but other senior members of the party would be stripped of their seats.
The court could also decide to throw out the complaint.
Pavin Chachavalpongpun, of the Centre for Southeast Asian Studies at Kyoto University in Japan, told AFP said the verdict was unpredictable.
"If you look back at the Constitutional Court in the past few years, you know they can do anything if that is to protect the interest of those who they work for... of the army, of the traditional elite, of the monarchy," he said.
In case of a dissolution ruling, "the supporters of the Puea Thai party would not stay quiet, there could be some sort of coming out in the street", he added.