The leadership of the Solomon Islands prime minister Sir Allen Kemakeza is to be challenged in parliament today.
The motion, to be moved by the Opposition leader Patteson Oti, comes after days of confusion in the government.
Last week, the finance minister, Laurie Chan, resigned and the cabinet was reshuffled.
And on the eve of the no confidence vote, Edward Huniehu has been sacked from Cabinet, and Paul Mainu, one of six MPs who had threatened to join the opposition ranks, has been sworn in in his place.
Mr Oti says there is a need for a change of leader because of the prime minister's behaviour and attitude towards the difficulties the country is experiencing.
Both the opposition and the government coalition are to retreat into camps to ensure there are no defections ahead of the vote.
A vote of no confidence planned by Mr Oti in April was called off amid claims of intimidation by both the oppostion and the government coalition. .
Meanwhile, the Australian Foreign Minister Alexander Downer has arrived in Solomon Islands for a brief visit.