TORONTO -- The head of the union for Toronto police officers is calling for the head of the province's police watchdog to step down.

Toronto Police Association president Mike McCormack issued a news release today making what he calls two "disturbing allegations" against the director of the Special Investigations Unit.

McCormack says Ian Scott told SIU officers not to arrest a man who was a complainant in an SIU case even though he had outstanding warrants for domestic assault.

McCormack also says the SIU alleged that a man was injured with a fracture in an "encounter" with a Toronto police officer, but a judge who later acquitted the officer found there was no fracture.

The union boss calls the allegations "shocking" and says Scott should resign until an independent inquiry can look at the allegations.

Scott -- who has previously been involved with a public spat with the Toronto Police Service -- says in the first case his officers told the man to speak to a lawyer and he turned himself in, and in the second case medical evidence did in fact show a fracture.

"Mr. McCormack is entitled to his opinion about my leadership of the unit," Scott said in his press release.

"Frankly, I would have been more surprised if he issued a news release saying he was happy with the way the unit is currently functioning."