Novak Djokovic in training ahead of this year's Australian Open, where he is top seed  ©Getty Images

Defending champions Novak Djokovic and Serena Williams have been installed as top seeds for this month's Australian Open.

The first tennis Grand Slam of the year will begin on Melbourne Park's hard courts on Monday (January 18) and the multiple winners will be the pair to beat in the men's and women's singles.

Twenty-eight-year-old Serbian Djokovic beat Britain's Andy Murray in four sets to win the 2015 tournament, a success which saw him add to four previous wins in 2008, 2011, 2012 and 2013.

The world number one also has three Wimbledon titles and two US Open crowns to his name, with the clay-court French Open remaining as the one Grand Slam to elude him.

Olympic champion Murray has been named as second seed with the former Wimbledon and US Open winner searching for a first title in Australia after being beaten in the final on four occasions.

Serena Williams is chasing a seventh title in Melbourne
Serena Williams is chasing a seventh title in Melbourne ©Getty Images

Seventeen-time Grand Slam winner Roger Federer is seeded third, with the 34-year-old Swiss a four-time winner in Melbourne, while his compatriot Stan Wawrinka, the 2014 champion, is ranked fourth.

Spaniard Rafael Nadal, another of the sport's heavyweights who won in Australia in 2009, is seeded fifth, while 23-year-old Bernard Tomic is the highest placed Australian at 16th.

Williams, meanwhile, is a six-time Australian Open champion with her success last year coming in straight sets against Russia's Maria Sharapova.

The 34-year-old American has won an incredible 21 Grand Slam titles and only missed out on the US Open prize during 2015.

Romania's Simona Halep, who is still chasing a first major crown, is seeded second ahead of Spain's 2015 Wimbledon runner-up Garbine Muguruza who is placed third.

Home hopes will be led by 25th seed Samantha Stosur, the 2011 US Open champion who has never made it past the fourth round at her home Grand Slam.

The men's draw will be missing Frenchman Richard Gasquet, with the world number nine the only member of the ATP World Tour's top 32 not to make Melbourne due to a back injury.

Women's US Open champion Flavia Pennetta is a notable absentee from the women's competition after the Italian retired after her success in New York.