Roger Federer has renewed his calls for stricter anti-doping measures in tennis, stating his belief that more funding should be put towards the issue.
Seventeen-time grand slam singles champion Federer has previously urged his sport's authorities to take a tougher stance when it comes to the fight against performance-enhancing drugs.
On Friday, the Telegraph quoted the Swiss as saying: "It's really hard for me to tell but with all the money we have in the sport, you would think they would have more funding for the anti-doping programme.
"That seems logical to me but maybe it's not so logical to get that money because we've had some issues in the past but it's not been all the time everywhere. But I would like to see more funding, no doubt about it, especially during the off-season.
"I would like to see more funding for when the players work the hardest. I've always said it - the best way is that you get tested every, let's say, quarter-final that you play in a tournament so you know there will be testers there when the prize money and the points go up.
"I think for the players' minds it will be a good thing to have, and for the off-season you don't want just a few countries to do their utmost and for other countries to never test. It needs to be across the board and that's why I think internationally it needs a lot of funding.
"How you get to that money is another debate but I think we could definitely do with more funding overall."
Federer also reiterated his view that he is capable of winning another major title, despite his last slam success coming back in 2012 at Wimbledon.
The 35-year-old claims to feel refreshed following a lengthy period on the sidelines through injury and said: "Maybe my body needed this more than I thought. I do believe it could be very beneficial to the future of my tennis career.
"The mindset is always very positive that it [winning another slam] can happen and should happen, and that I'm doing everything I possibly can to achieve that.
"I'm very positive with my team of winning another major and winning the tough matches, and physically to be in tip-top shape when that slam semi or final comes around."