Toronto Mayor Rob Ford has advised the city clerk he will return to work on June 30 after spending several weeks in treatment for alcohol abuse.

"Kindly be advised that I will be returning to work at City Hall on Monday, June 30th, 2014, in the later portion of the afternoon, to resume my duties as mayor," writes Ford in a letter to Ulli Watkiss.

"Please make the necessary arrangements for my locks to be restored to their state prior to my departure, for 1:00 p.m. on the date of my return."

Since early May, Ford has been undergoing treatment for substance abuse at a rehabilitation centre in Bala, Ont., about 200 kilometres north of Toronto.

He entered the treatment program after a year of scandal surrounding his office that included the emergence of videos that show him inebriated, ranting and, in one instance, holding what appears to be a crack pipe. In November, council voted to strip Ford of many of his powers, leaving him as little more than mayor in name only.

Ford is seeking re-election in the Oct. 27 municipal vote. He had announced a leave of absence on April 30 to "seek immediate help" for alcohol addiction.

"I have a problem with alcohol and the choices I have made while under the influence," Ford said in a statement issued that day. "I have struggled with this for some time. I know that I need professional help, and I am now 100 per cent committed to getting myself right."

That admission came after Ford spent much of the previous year denying he had an alcohol or substance abuse problem. In November, he told CBC's Peter Mansbridge he was "done" with alcohol after having a "come-to-Jesus moment."

Then in April of this year, media reports pointed to two new recordings of Ford acting badly. In an audio recording posted by the Toronto Sun, Ford is heard making lewd remarks about councillor and mayoralty rival Karen Stintz. In a video viewed by the Globe and Mail, Ford is seen smoking what the paper said "a self-professed drug dealer" described as crack cocaine.

Those revelations prompted Ford's decision to seek professional help.

In May 2013, the crack scandal surrounding Ford made international headlines with media reports of a yet-to-surface tape showing Ford smoking crack.

Since then, Ford has become regular fodder for television comics and the Ford story has made headlines around the world. Many members of council continue to call for Ford to resign, though he also appears to have considerable support from some voters, particularly in the suburbs that ring Toronto.