The Fiji Democratic Party is demanding the pro-coup Conservative Alliance Matanitu Vanua Party explain why it wants an 1874 document ceding control of Fiji to Britain written into the constitution.
In the Deed of Cession Fiji's leading chiefs handed control of the country to Queen Victoria.
The leader of the Democratic Party, Filipe Bole, says the move by the Matanitu Vanua Party and it senior government coalition partner, the SDL, is strange and playing on the ignorance of villagers.
Mr Bole, who was the chairman of the Parliamentary committee which drew up the 1997 Constitution, says unless the two parties give reasons for their demand they would be insulting the people of Fiji.
He says an agreement for Fiji to give its sovereignty to another country is not something to celebrate.
"normally we would want to celebrate our independence, rather than the giving away of our sovereignty and I wanted someone in the Matanitu Vanua Party to explain for the public to know why they wanted the Deed as part of our constitution"