Police in Tonga are investigating a letter that was said to be falsely attributed to the Prime Minister on a local website.
The letter, dated January 9, claims to have been written by 'Akilisi Pohiva to the 'Publicity Department of the Communist Party of China.'
It stated that "religion and its institutions" were halting Tonga's progress and preventing it from transitioning into a democracy.
It went on to speak of creating a confidential plan to secularise the country and eventually remove all power from the monarchy.
The Prime Minister's Office has vehemently denied the letter was penned by Mr Pohiva and the Chinese Embassy has questioned its veracity.
Tonga's Police Commissioner said an official complaint had been received from Mr Pohiva and the matter was an issue of national security.
Steven Caldwell said he had directed that the matter be given urgent priority.