QUEBEC CITY - Quebec Premier Jean Charest's second-in-command is walking away from politics.

Nathalie Normandeau, the province's deputy premier and natural resources minister, made the surprise announcement Tuesday in Quebec City.

The decision triggers a sudden departure for a high-profile cabinet minister some believed could one day succeed Charest as leader of the provincial Liberals.

"Political life is a demanding life," Normandeau, 43, said as she stood beside Charest at a news conference.

"It is time to pass the torch."

Normandeau, who was first elected to the provincial legislature in 1998, was one of Charest's most-trusted ministers over the last few years.

Most recently, she was responsible for Quebec's massive energy and mining development program for its north -- known as the Plan Nord.

Normandeau served as municipal affairs minister from February 2005 until June 2009, when she took over the natural resources dossier.

But along with her considerable cabinet experience and high profile, she was also at the centre of recent controversies.

Normandeau faced heavy criticism from environmentalists and landowners over the past year for her defence of Quebec's fledgling -- yet the highly contentious -- shale-gas industry.

She was also attacked by the opposition Parti Quebecois for maintaining a relationship with former Montreal police chief Yvan Delorme, who himself has come under fire amid corruption allegations.

It wasn't the first time one of her relationships had made headlines in the province: Normandeau also dated fellow MNA Francois Bonnardel, a member of the opposing Action democratique du Quebec.

But she has also claimed some victories for Quebec.

Earlier this year, Normandeau signed an agreement with Ottawa that gives Quebec 100 per cent of the royalties from the so-called Old Harry oil and gas reserve in the Gulf of St. Lawrence.

The deposit, estimated to hold two million barrels of recoverable oil, has been the source of a long-running interprovincial feud because it straddles a disputed boundary between Quebec and Newfoundland and Labrador.

Many speculated that Normandeau could one day contend to become Liberal leader, though she likely would have had to improve her English.