Parliament will now meet from March 5 at the Tonga National Centre.
The centre was previously excluded as a parliamentary venue as it was located outside Nuku'alofa's boundary.
A revision has been made to include the centre within the capital's boundary so as to comply with the country's constitution which says the Legislative Assembly shall always meet in the capital except in times of war.
Initially the Fa'onelua Convention Centre was selected as the new seat of government.
The Tonga National Centre will remain the home of the Legislative Assembly until a new complex is built.