B.C.'s police watchdog is investigating after Vancouver police officers' response to a complaint about someone spitting at people ended with a suspect being Tasered and catching fire.

Police were called to the area near Jack Poole Plaza around 2:15 p.m. PT on Monday, according to the Independent Investigations Office (IIO).

A statement said someone had called police to say a man had spat at a couple and later tried "to touch a number of women" in the area.

The IIO said responding officers found the suspect along the seawall about half a kilometre away, near Bute Street and Cordova Street.

The agency said the officers used a Taser to subdue the man after he tried to fight, but a barb from the Taser caught "a flammable concealed possession" hidden on the suspect. The object burst into flame.

The suspect was taken to hospital with serious, but not life-threatening injuries.

The IIO is now investigating to see what role, if any, officers' actions or inactions played in the man's injuries.

The agency released a statement Wednesday saying it is looking for witnesses to the incident. Anyone with information is asked to call 1-855-446-8477.