DUBAI (Reuters) - Twice major winner Mark O'Meara believes former world number one Vijay Singh should be suspended by the PGA Tour after the Fijian admitted to using a spray to treat an injury which contains a banned substance.

The three-times major winner said he was unaware the deer-antler spray, which he has been using for a couple of months, contained an insulin-like growth factor that is banned by the U.S. circuit.

O'Meara, competing at the Dubai Desert Classic where the 56-year-old opened with a five-under-par 67 on Thursday, said Singh should be banned "for a couple of months" by the PGA Tour.

O'Meara said he was "surprised" to hear the news and although he thought it had no influence on Singh's game, the 49-year-old "had to pay the price".

Singh allegedly paid one of Sports with Alternatives to Steroids (SWATS) owners $9,000 in November for the spray and other products, Sports Illustrated said earlier this week.

Singh released a statement on Wednesday at the Phoenix Open confirming he had taken it, that he was "shocked" and "angry" at himself and that he was in cooperating with the tour over the issue.

(Writing by Tom Pilcher in London; Editing by John O'Brien)