LOS ANGELES, Oct 11 — Canadian rock band Sum 41 frontman Deryck Whibley has accused the band's first manager, Greig Nori, of grooming and sexually abusing him, from when he was a teenager.

In an interview with the Los Angeles Times, the singer says he kept the dark side of the relationship secret from his bandmates for years.

Whibley's memoir, Walking Disaster: My Life Through Heaven and Hell, which was published on Tuesday, documents the band's early years in the Toronto music scene and its rise to international stardom, with its beginning aided in part by Nori — then in his 30s and the frontman of a popular Canadian indie band. He met Whibley after a show and begin to mentor him.

Nori later became the band's manager.

Whibley said one night, Nori suddenly, "passionately” kissed him in a bathroom stall at a rave, surprising and confusing the then 18-year-old, who was high on ecstasy at the time.

He alleges Nori coerced him into an unwanted sexual relationship that lasted about four years.

"Greig kept pushing for things to happen when we were together,” he writes in the memoir, according to the Toronto Star.

"I started feeling like I was being pressured to do something against my will.”

When the physical relationship ended, Whibley, now 44, alleges Nori continued with verbal and psychological abuse.

Whibley alleges he revealed the relationship to his former wife, Canadian singer Avril Lavigne, who said: "That's abuse! He sexually abused you.”

The couple were married from 2006 to 2009.

The Sum 41 singer told the Toronto Star in an interview that he thought the relationship with Nori would be "a deep, dark secret I was going to take to my grave”.

"But I didn't know how to tell the story [of the band] without it, because it was so intertwined with everything that was going on in my life back at that point, almost on a daily basis.”

The band parted ways Mr Nori in 2005.

Nori meanwhile told the Globe and Mail that Whibley's claims were "false allegations”, and said he had retained a defamation lawyer.

In a statement to the Toronto Star yesterday, Nori said that: "The accusation that I initiated the relationship is false. I did not initiate it. Whibley initiated it, aggressively.”

He said the relationship eventually "faded out. Consensually”.

Whibley told the LA Times he did not warn Nori about the allegations in the memoir before it was published.

"I’ve had an inner battle, like, ‘Why do I want to tell him? Because I feel like I’m supposed to? Because he still has this thing over me?’”

Sum 41 are currently on their farewell world tour and will be disbanding after 28 years together.