Three of the Parti Quebecois' most influential members abruptly quit their party Monday, saying the pro-independence party has become obsessed with gaining power at any cost.

The three political heavyweights include: actor-turned politician Pierre Curzi, veteran Louise Beaudoin and Lisette Lapointe, wife of popular former premier Jacques Parizeau.

"I no longer feel in my place," Lapointe said at a news conference in Quebec City Monday.

Only weeks ago, the Parti Quebecois seemed to be on its way to easily regaining power in the next election.

But then their cousins, the Bloc Quebecois, imploded in the federal election. And Parti Quebecois Leader Pauline Marois said the party would support a contentious private member's bill over the Quebec City arena project.

The law would have protected the arena from court challenges, which experts have called legally dubious policy.

That appeared to be the final straw for the departing trio, who said they didn't appreciate being forced to support the legislation without being consulted on it.

CTV Montreal's Kai Nagata said no one saw the move coming.

"You can say the press gallery was in total shock," he said Monday from Quebec City.

Nagata said there was rumblings of discontent over the Quebec arena policy, but no one thought the split was so serious members would quit over it.

The trio was still negotiating with their former party as late as 10:15 a.m. Monday morning, before deciding to announce they had quit the caucus.

They say they will serve as independents and will continue to fight for sovereignty.

The proposed bill would block any challenges to the naming rights for the proposed Quebec City arena, struck between the city and the Quebecor media empire.

The three departing politicians are concerned the bill would effectively take away the right of a citizen to challenge government contracts in the future, Nagata said.

But Nagata says the arena controversy is the symptom of bigger problems within the Parti Quebecois, particularly a concern about the centralization of power.

With files from The Canadian Press