The country’s Crown Law office published an official “instrument of dissolution” signed by the monarch which dissolved parliament and called an election in November.
“(I) do lawfully dissolve the Legislative Assembly… and do command that new representatives of the nobles and the people be elected… no later than November 16,” it said.
The decree said King Tupou acted after receiving advice from the parliamentary speaker Lord Tu’ivakano but did not give a reason for the unprecedented action.
However, Pohiva, who was elected in late 2014, survived a motion of no confidence earlier this year brought by nobles who alleged the former democracy activist was not competent to lead the country.
Tonga is the Pacific’s only monarchy but has attempted to increase democratic representation in recent years. It has a 26-seat parliament with 17 members elected by the people and nine spots taken by hereditary nobles.
Since his coronation in 2012, Tupou has continued the work of his father in extending democracy in Tonga.
The moves were promoted by rioting in the capital Nuku’alofa in 2006 that left eight people dead, sparked by anger that reform of the semi-feudal political system was progressing too slowly.
The country has been peaceful since then but Kalafi Moala, publisher of the Taimi ‘O Tonga newspaper, said there was widespread frustration at Pohiva’s performance.
“There were very high expectations when he took office because he had been a leader of the pro-democracy movement,” he told AFP. “But there were a lot of problems and his government didn’t really deliver. He was very good in opposition but found it very difficult as prime minister.”
He said Pohiva had weakened the education system, caused problems with public enterprises and persecuted journalists for asking hard questions of the government.
Moala said a recent auditor’s report had also found irregularities in the books of numerous government agencies. He added that most Tongans backed the king’s decision.
“There’s a lot of shock, simply because this hasn’t happened before,” he said.
“Pohiva has a core of supporters and they’re out there on social media expressing disappointment. But I think most people are happy and felt like this had been coming for some time.”