Sum 41, seen at the MuchMusic Video Awards in Toronto in June, have cancelled their remaining Canadian dates. ((Adrian Wyld/Canadian Press) )

Rocker band Sum 41 has cancelled the remaining Canadian dates for its Strength in Numbers tour, after frontman Deryck Whibley injured his back.

A spokesperson for the band, which isfrom Ajax, Ont., announced that all remaining Canadian dates have been scrapped, including concerts scheduled for Toronto,Ottawa, Montrealand St. John's.

The band, now promoting its new album Underclass Hero, had been touring with fellow rockers Finger Eleven.

According to sources, Whibley suffered a herniated disc that flared up during a recent concert in Alberta.

The singer, who is married to Canadian pop-rock star Avril Lavigne, is said to be recuperating at their home in Los Angeles.

Tour promoter Live Nation said ticketholders can obtain refunds at point of purchase.

In February 2005, the band cancelled a string of Canadian concerts after Whibley's vocal cords became infected.

The band's website still lists upcoming concerts in Florida as well as further dates in the U.K. through November and early December.

With files from the Assocated Press