The speaker of Tonga's parliament says he had to ask the King to dissolve parliament as the government was working to concentrate power within cabinet.
Lord Tu'ivakano approached King Tupou last week, who called a snap election.
In a four page statement, Lord Tu'ivakano said he had been concerned with a series of unconstitutional decisions made by the government of 'Akilisi Pohiva since 2014.
These included the push to sign foreign treaties, Mr Pohiva's alleged shielding of an MP convicted of bribery, and his decision to withdraw from hosting the Pacific Games.
But he said he sought the King's intervention when it became apparent that cabinet was trying to concentrate power within it.
Lord Tu'ivakano said a new bill tabled last week sought to remove the privy council's role in appointing positions like the police commissioner and attorney general.
The appointments would instead be made by cabinet.
Lord Tu'ivakano said it was clear the government was trying to wear away the powers of the King and Privy Council, which he could not abide.