LONDON: World number one Novak Djokovic and 20-time Grand Slam champion Roger Federer were both named on the list of players for the Tokyo Olympics on Thursday -- a boost for a tournament hit by high-profile withdrawals.

Women's world number one Ash Barty and Japan's Naomi Osaka head the field in the women's singles.

A first-time gold-medal winner is assured in the women's singles with Puerto Rico's defending champion Monica Puig unable to compete because of injury.

Two-time champion Andy Murray, whose ranking has slipped to 118 as he battles to come back from hip surgery, will be aiming to win gold for the third Olympics in succession.

Djokovic, who is bidding at Wimbledon to match Federer and Rafa Nadal's record Grand Slam haul, won a singles bronze medal at the 2008 Olympics in Beijing when Federer won doubles gold.

An Olympic singles gold is the one major prize that still eludes the two players who are vying, along with Nadal, to be considered the greatest of all time.

A total of 46 nations will be represented at the Olympic tennis event which will be held at the Ariake Tennis Park from July 24 until Aug 1.

Several big names will not be travelling to Tokyo including former singles and doubles gold-medallist Rafa Nadal, four-time gold-medallist Serena Williams, US Open champion Dominic Thiem and Romanian two-time Grand Slam winner Simona Halep.