The Papua New Guinea Opposition has undergone an unofficial leadership change with at least 14 MPs voting for Andrew Baing to take over the post over Sir Mekere Morauta.
The move comes after indications by Sir Mekere that he could join the government coalition.
However Sir Mekere says the meeting where the vote was held was illegal.
Our correspondent in Port Moresby Peter Niesi says a ruling will be made soon on whether the vote stands:
"Interestingly, Sir Mekere Morauta himself, highlighted that this issue needs to be sorted out, and it really needs to be sorted out by the speaker of parliament, by the acting speaker Jeffrey Nape, or by the registrar of political parties, Paul Bengo, and until those two come in and sort these issues out, which includes a referral to the Ombudsman Commission, the uncertainties remain."