The Solomon Islands opposition leader Fred Fono says 12 MPs who have resigned from the government are committed to removing Prime Minister Manasseh Sogavare.
Nine cabinet ministers and three backbenchers reportedly resigned from government at the weekend, saying they no longer have confidence in Mr Sogavare's leadership style.
The opposition has requested the Governor General call an urgent meeting of Parliament within the next seven days so they can submit a motion of no confidence if Mr Sogavare does not resign.
Mr Fono is confident that despite previous failed attempts to lure government MPs over, the opposition grouping now has up to 30 MPs.
He says the defections are due partly to the damage caused by Mr Sogavare's support for the embattled Attorney General Julian Moti.
"That's one of the reasons for the shift in allegiance. The Solomon Islands' image has been tarnished regionally and internationally and we are at our lowest peak in terms of our international reputation."