Solomon Islands is in a political crisis after three senior government ministers resigned from cabinet on the eve of new Prime Minister Matthew Wale's arrival at the Pacific Island Forum Leaders' Meeting in Palau.

Mr Wale, who was elected the country's leader a little more than 100 days ago to head the Government for Reform, Empowerment, Accountability and Transformation coalition, is set to face a motion of no confidence on his return home on Friday.

This comes after Minister for Home Affairs, Manasseh Maelanga, launched a leadership challenge on Monday.

The move saw Minister for Commerce, Industries, Labour and Immigration, Harry Kuma, and Minister for Justice and Legal Affairs, Clezy Rore, to join Mr Maelanga in quitting their cabinet positions.

The Prime Minister had won tentative support largely from his Solomon Islands Democratic Party MPs in a tight 26-to-22 parliamentary vote against independent rival Peter Shanel Agovaka.

Solomon Islands Governor-General's deputy private secretary confirmed the ministerial resignations on Monday.

A government statement said the parliamentary clerk only received the no-confidence motion as Mr Wale departed the Solomon Islands for the Pacific Islands Forum.

Mr Wale was in the dark on his arrival to Palau over the internal political rumblings.

"When I know, I'll tell you more," he told media.

Minister for National Planning, Peter Kenilorea Jr, who accompanied Mr Wale, was unaware of what was behind the division.

He said the government would deal with the matter in time while maintaining its focus on the Pacific Islands Forum.

"It's just one of these things that we have to deal with, that sort of thing," Mr Kenilorea Jr said.

According to Mr Maelanga, the no-confidence motion was over Mr Wale, who "repeatedly made decisions on matters of national importance without properly consulting cabinet".

Solomon Islands media have described the turn of events as an "internal coalition revolt" while regional Pacific observers argue the timing is deeply unfortunate.

The motion presents an early political test for Mr Wale's government that could expose divisions within its shaky coalition.

The two men were previously rivals for the Prime Minister leadership until Mr Maelanga withdrew his candidacy just ahead of the vote.

Mr Wale's challenge comes as he focuses on handing over the outgoing Pacific Islands Forum chairman role to Palau President Surangel Whipps Jr.