Premier Dalton McGuinty has called a byelection for the provincial riding of Toronto Centre, and environmentalist Glen Murray has been nominated as the Liberal candidate.

"I have spent my life working with people at the community level to strengthen social services and create friendly, green urban environments that will prosper in the 21st century," Murray said in a press release.

"I am running to be the MPP for Toronto Centre because I believe my priorities find their best expression in the leadership of Premier Dalton McGuinty and the Ontario Liberal government."

Murray is the former mayor of Winnipeg and current president and CEO of the Canadian Urban Institute.

The byelection will take place Thursday, Feb. 4. Provincial law stipulates that an election must be called on a Wednesday and held on the fifth Thursday after the writ was issued.

The riding was previously held by former deputy premier George Smitherman. He stepped aside from his seat last weekend, so that he can put together a bid to become the next mayor of Toronto.

The NDP is expected to nominate affordable housing advocate Cathy Crowe.

It is not known who will seek the nomination for the Progressive Conservatives. The party plans to nominate its candidate next week.

Toronto Centre stretches from the southern boundary of Mount Pleasant Cemetery south to Lake Ontario. It is bounded on the east by the Don River and on the west by Yonge Street and Avenue Road.

There are 114,851 people in the riding. It is home to some of the city's wealthiest residents, mainly in Rosedale, and some of its poorest in Regent Park. Toronto's gay village is centred around Church and Wellesley Streets. Murray is openly gay.

Smitherman, first elected in 1999, polled 21,522 votes in the 2007 general election. Progressive Conservative candidate Pamela Taylor placed second with 9,084, while the NDP's Sandra Gonzalez placed third with 8,464. Mike McLean of the Green Party placed fourth with 4,412 votes.

The byelection will be the second test for the McGuinty Liberals in Toronto since the 2007 general election. Dr. Eric Hoskins held the mid-town St. Paul's seat for the party following a mid-September byelection in which the McGuinty government came under fierce attack for the eHealth scandal and its HST tax harmonization policy.

With files from The Canadian Press