Closing a session of Parliament a week later, the king said, "Let us rebuild a new capital and a new Tonga."
The announcement, the news agency said, is part of that promise.
Already this year, two other countries saw the end of monarchy.
In March, Bhutan held elections that ended more than 100 years of royal rule in the South Asian nation and transformed it into a democracy.
Two months later, neighboring Nepal declared itself a republic following the elections for a new Constituent Assembly that abolished a 239-year monarchy.
Nepal Sees Shaky Start as Monarchy Gives Way to Republic
Nepal's Maoists, which won the largest number of seats but fell short of a majority in April's general elections, had said they will not form a government because their choice of president was rejected by rival lawmakers.
However, the Maoists offered to reverse a decision to boycott forming a government in a compromise that could steer the newly republican country out of a new political crisis. The preconditions set by the Maoists include the need to end the alliance of Nepali Congress (NC), the Communist Party Nepal-Unified Marxist Leninist (CPN-UML) and Madheis People's Rights Forum, to prepare a common minimum program and give the vote of confidence to the government for at least two years.
The Maoists' continued involvement in mainstream politics is seen as crucial to the survival of the peace process. They are also the only party with enough seats to form a stable government.
Let's review that key sentence: "The Maoists' continued involvement in mainstream politics is seen as crucial to the survival of the peace process." By whom? Newly arrived aliens who have never before heard of Maoists?