The Quebec Liberals could be left with the unhappy task of propping up their arch-rival, the Parti Québécois minority government, in a vote on the upcoming budget.

That's because the other opposition party, François Legault's Coalition Avenir Québec, has sent a signal that it's unlikely to support the budget to be tabled next Tuesday.

Legault says his 19 elected members will all be present to vote against the budget unless it satisfies four conditions: no tax hikes, no delaying the return to a balanced budget, scrap a $200-a-year-health tax as promised in the PQ election platform, and include an economic action plan.

Given the challenge of satisfying all those conditions — especially in a budget due to be tabled in just a few days — that leaves slim chances of the CAQ propping up the government.

That could leave one other option: the Liberals.

The official Opposition, which was turfed from power in September, is in the midst of a leadership race and therefore less likely to trigger an election.

The PQ even timed the release of its budget to coincide with that race. Provincial budgets are usually tabled in the spring, and this one is coming out months earlier than usual.

The Marois government has only a four-seat lead in the legislature and needs the support of the Liberals or the CAQ to pass legislation or, in this case, to survive a confidence vote.

Legault is leaving little hope that his party will be the one to save the PQ.

He says he's not encouraged by what he's seen from the government so far, and adds that Premier Pauline Marois is "living in a parallel universe" if she thinks Quebecers will easily accept tax hikes.