The Governor-General of Tuvalu has issued a proclamation removing the prime minister Willy Telavi and appointing the opposition leader Enele Sopoaga as caretaker prime minister.
He has also ordered parliament to meet and that is now underway.
Islands Business reports the Governor General, Sir Italeli Iakoba, as saying his staff had sent letters to all members of parliament and the police commissioner announcing his action.
PACNEWS reports that opposition MP, Taukelina Finikaso, said Mr Telavi earlier made a public announcement that he would be removing the governor general.
He says the Governor General as the Queen's representative in Tuvalu has the powers to uphold the constitution.
Mr Finikaso says if the speaker and the government are not following the constitution, the people of Tuvalu need to rely on the Governor General's judgment on this matter.
On Wednesday, the speaker adjourned parliament, saying the resignation of a Cabinet Minister forced the move.
But this came as the opposition, with a clear majority of support among the 15 MPs, planned a motion of no confidence in Mr Telavi.
The ministry of communications confirms parliament is sitting but that no vote has been held.
An official says so far debate has focussed on the legality of the governor general's proclamation.