Controversial anti-doping rules requiring athletes to state their location for an hour every day will need at least a year to "bed in", the World Anti-Doping Agency (WADA) said on Tuesday.
"We're eight weeks into this and I don't know of anyone who has missed a test yet," WADA president John Fahey said of the new rules that came into effect on Jan. 1.
"Surely it is best to monitor it and if there are shortfalls that emerge than we can look at it again next year. We've read about complaints from various people but nothing has been put to us directly," he told a media briefing.
Under the new requirements, athletes have to inform their national anti-doping authorities of where they will be at a chosen hour between 6 a.m. and 11 p.m each day for a three-month period.
If they change their plans they are obliged to inform the authorities of that change.
Athletes who miss three doping tests over an 18 month period due to not being where they said they would be face possible suspensions from their sport.
The new regulations have been criticised by a number of athletes groups for overly intruding into their private lives.
Several top tennis players, including Rafael Nadal, Andy Murray and Venus Williams, have argued that the rules are harder to stick to in sports where schedules are subject to sudden changes.
"There seems to be a momentum of opposition gaining over the last few days that is probably a little skewed," said WADA director general David Howman.
"We've had various forms of whereabouts requirements in place for 10 years now even though some sports are just confronting it for the first time.
"I think some people are just reacting negatively to change. But it's clear that we need out of competition testing because generally speaking that's when (cheating) athletes are doping up.
WADA is already facing at least one potential legal challenge to the new rules in Belgium where a group of 65 athletes, including cyclists and volleyball players, are hoping to prove that the regulations break EU privacy laws.
Howman said on Tuesday that he was surprised the athletes involved even thought that they would be affected by the changes.
"The new whereabouts rules only apply to athletes who are considered part of each country's small group of elite international athletes and as I understand it that is not the case with the majority of the Belgian group."
Howman also said that WADA had received no communications from EU sports commissioner Jan Figel over his publicly stated concerns about the regulations.
Figel said last week that he would be meeting Fahey in Lausanne this week to discuss the issue but Howman said they had not heard of any such meeting.
"We will however engage in dialogue with all those who express appropriately founded criticism," Howman added. "We have talked repeatedly to EU Commission members and will continue to do so.
"But it makes no sense to change things already based on a few complaints in the media."