152 Tongans have signed a writ calling for a judicial review of new media laws and amendments to the Tonga constitution.
Matangi Tonga magazine reports the writ is expected to be tabled with the Supreme Court within two weeks.
The signatories say the changes curtail freedom of speech.
The laws earlier this month were used to stop the sale in Tonga of the New Zealand produced Taimi O Tonga paper after its owners were denied a renewal of their licence.
The Pro-Democracy MP, Fred Sevele, says the plaintiffs represent a large cross-section of Tongan society, including seven of the nine people's representatives.
He says this shows the depth of opposition to the government's moves.
"This is the first time that the citizens of Tonga across the whole of the country have decided to do this and it shows the dislike of the amendments that were made and the importance of retrieving what we have lost through the parliament."