Peter Dawson, the chief executive of the Royal & Ancient, last night denied that golf had become complacent on the issue of drug taking.

Vijay Singh, the three-time major winner and former world No.1 from Fiji, is at the centre of a US PGA Tour investigation after he admitted to using a deer antler spray previously found to contain a prohibited growth hormone.

Dawson admits the high-profile Singh saga will lead to a period of "soul searching" for the game of golf but steadfastly stands by his belief that widespread use of performance-enhancing substances is not commonplace.

The R&A was the driving force behind anti-doping in golf and piloted drug testing at the World Amateur Team Championship in 2006. The St Andrews-based governing body then introduced the procedure at the Open in 2009 at Turnberry and have continued testing at the Open as well as a number of leading amateur events that are under its administrative umbrella.

Dawson said: "Obviously we begin to wonder 'is this going on a lot?' Over the years I've become pretty confident, and I hope not complacent, that there isn't a lot of it going on. I don't think we have been complacent but I won't deny that when something like this happens it does make you think.

"To find the substance that allegedly is contained in deer antler spray, you need a blood test rather than the urine test that is going on in golf. You begin to wonder if your testing regimes are right. This is going to cause a lot of soul searching and I wouldn't be surprised if there are changes [to procedure]".