The government of Prime Minister Manasseh Sogavare is facing a vote of no confidence in parliament next week, after a series of defections from the government.
Mr Sogavare on Thursday announced moves to consolidate his coalition government, announcing eight new ministers.
But in a statement, the opposition group said that consolidation had included attempts at bribery.
It accuses the forestry minister Bradley Tovosia of trying to bribe MP Alfred Ghiro with cash and the fisheries portfolio, which he rejected.
