OTTAWA (AFP) - Police reopened an investigation into illicit drug use by Toronto's scandal-plagued Mayor Rob Ford, who left for rehab Thursday after a new video emerged allegedly showing him recently smoking crack.

"Investigators would be interested to see what new information there is" in the case, Toronto police spokesman Mark Pugash said in a statement.

Ford announced late Wednesday that he was taking a leave of absence in order to enter rehab, even as he continues his bid for re-election.

Television cameras showed the mayor leaving his home in the early morning, with a large stuffed suitcase in tow.

Ford, 44, has already admitted to binge drinking and smoking crack and has been campaigning on a give-me-another-chance platform.

The Globe and Mail newspaper published a screen grab from video it said its reporters had viewed, in which Ford is seen holding a metal pipe alleged to contain the addictive cocaine derivative.

In the full video, which the paper said was shot by a self-described drug dealer, the mayor of North America's fourth largest city is seen taking a hit from the copper-colored pipe, exhaling a cloud of smoke and shaking his right hand frantically, the Globe and Mail said.

The dealer says the video was shot in the early hours of Saturday in the basement of the home of Ford's sister Kathy, who has struggled with drug addiction herself.

A man resembling Alessandro Lisi - the mayor's former driver who has been charged with drug dealing and extortion - and Kathy Ford are also seen in the video, the Globe and Mail said.

The newspaper said it had been offered an opportunity to buy the video but declined, and instead paid US$9,100 (S$11,400) for still images from it.

Editor-in-chief David Walmsley said this was "not our normal practice" but added it was important for voters to "have all the facts about who is running Canada's largest city, especially in the middle of a mayoralty campaign."

In a separate audio recording of the mayor at a bar on Monday, obtained by the Toronto Sun, Ford reportedly complains about his wife Renata and makes lewd comments about mayoral candidate Karen Stintz, saying: "I'd like to (expletive) jam her."

Stintz reacted at a press conference Thursday, saying: "Rob Ford's comments are gross."

"I am disappointed with the misogynist language used by Rob Ford," she said. "Rob Ford needs to get help."

"Mr. Ford needs to pack up his circus," another mayoral candidate, Olivia Chow, said. "He has offended many and hurt many."