Novak Djokovic has suggested that the current anti-doping program in tennis is sufficient, even saying that some the requirements are too extensive.

Djokovic's comments came as the top eight players spoke to media before the ATP World Tour Finals, where Roger Federer and Andy Murray called for more testing and resources and Rafael Nadal said he wanted the testing done on players to be made more public.

Djokovic indicated he did not have a problem with the system in general. "I think they are randomly selecting the players and the locations where they are going to test the players. I’m always available. They know where I am. I’m not hiding anything, so if any testers come to me I think it’s fair enough," he said.

Djokovic has previously criticized the program for suspending compatriot Viktor Troicki, who did not give a test when requested but said an official had given him permission to not do it.

The tennis anti-doping program, which is administered by the ITF and financed by contributions from the ATP, WTA, ITF and Grand Slams, has increased its testing significantly since introducing a biological profiling component two years ago.

According to its more recent statistics, the program conducted more than 3,500 tests annually, including more than 1,400 which were not in-competition. Top 50 ATP players are generally tested more than seven times a season, and top 50 WTA players between 4-6 times, according to the statistics.

However, Djokovic added that the whereabouts requirements which call for the Top 50 singles players to identify their location for an hour each day for the year are too onerous, particularly during the offseason.

"The whereabouts demands are a little bit too much and a bit unnecessary to write where you are every single day of the year," he said. "If you don't appear at the place where it is written down then you get a warning, then two warnings and then suspension. I think that is a bit too much.

"The tennis season is very long. They know where we are and they can find us. When you're in the off-season you are going back and forth and changing cities and locations and it can be hard to track down and fill in the whereabouts sheet."