The leaders of two opposition parties and a senior trade union official in Fiji have spent the night in jail after they took part in an event critical of the country's constitution, an opposition party official says.
The leader of the National Federation Party (NFP), Biman Prasad, and a trade unionist, Attar Singh, were taken into custody over their participation in Wednesday's forum on the 2013 constitution, said NFP official Prem Singh.
"The arrest is a threat to public assembly and we don't know why they are being arrested, they are only doing their jobs," Singh said, but added that no charges had yet been made.
In a statement, the Sodelpa opposition party said its leader Sitiveni Rabuka, a former prime minister, had turned himself in to police.
Police are also holding a former politician and an official of a non-government body that organised Wednesday's event, Radio New Zealand said. The event coincided with the Pacific island's first public holiday for Constitution Day.
Speaking to the Australian Broadcasting Corporation the day before the event, Prasad had described the holiday as a "waste of money" and government "propaganda".
"There is nothing much to celebrate about the 2013 constitution, which was opposed to the will of the people," Prasad said.
Prasad's wife, Rajni Chand Prasad, said police had searched their house looking for documents and that police also searched his office and took away a laptop computer.
Fiji's Prime Minister Frank Bainimarama came to power in a bloodless military coup in 2006. He stood down from the military to run as a civilian in the country's 2014 elections, winning by a landslide.