Toronto Mayor Rob Ford has acknowledged a drug problem for the first time and vowed that his commitment to "living clean is now unwavering'' as he returned to work after a two-month stay in a rehabilitation clinic.

Ford said on Monday that he had been in "complete denial" about his drinking and drug use before entering the clinic and admitted that his struggle against substance abuse would never end.

Ford made comments as he returned to city hall and rejoined a re-election campaign where he was running in second place, according to a recent poll. He took leave on April 30, saying at the time that he needed to deal with an alcohol problem.

"For a long, long time I resisted the idea of getting help. Like a lot of people dealing with substance abuse, I was in complete denial. I had convinced myself that I did not have a problem," Ford told reporters, at points appearing to fight back tears.

"Substance abuse is a very, very difficult thing to overcome but I will keep battling this disease for the rest of my life."

The mayor entered rehab after months of denials that he had a substance abuse problem and nearly a year after a media report surfaced that he appeared in a video smoking crack.

Ford became famous globally after he admitted that he had smoked the drug while in a "drunken stupor".

Source: Agencies