The Papua New Guinea Prime Minister, Sir Michael Somare, is coming under increased pressure to step down, possibly in favour of his deputy Sir Puka Temu, a former deputy Don Polye, or his son Arthur Somare.
Lobbying for a change in the government has intensified following a Supreme Court ruling overturning parts of the Organic Law on the Integrity of Political Parties and Candidates.
That law had restricted opportunities for MPs to switch their allegiance.
Various political factions held meetings last weekend to weigh up their numbers for possible changes of government or the leadership.
Government insiders say there's pressure on Sir Michael to relinquish his job while the Opposition sent an open invitation to Government MPs to cross over and be part of a better government.
But our correspondent reports that toppling the Somare Government will be difficult, given the support it currently has.
Oseah Philemon says the coalition of 13 parties includes nearly three quarters of the MPs in the 109 seat Parliament.
"It's a very tough battle for the opposition. The Government is very much intact and you need at least 40 members for instance to feel comfortable in moving a vote of no confidence in Sir Michael. Otherwise as it stands now the Government is still very much intact."