A nephew of King Taufa'ahau Tupou the 4th says he could be charged with treason by the Tongan government.
Prince Uluvalu Tu'ipelehake, who is also a member of parliament, wrote to the Australian Foreign Affairs minister Alexander Downer, asking him to use his influence to bring more democracy to Tonga's political system.
The letter said many people were disheartened by recent amendments to the Constitution and the introduction of Acts which were seen as obstacles to their liberty.
Prince Tu'ipelehake also said Tongans were unhappy about being ignored by government and he said he wanted a more balanced representation in parliament.
He says the letter has been passed on to the ministry of justice and he has been told he could be charged with treason and slander.
Prince Tu'ipelehake says it is personally difficult to speak out because of his family connections.
"They had a special cabinet meeting and they decided to hand my letter to the ministry of justice for them to sight and I could possibly be charged with treason and slander. So I guess that's the government's reaction."
Prince Tu'ipelehake denies he has committed treason or that his letter was slanderous.