Novak Djokovic has been named in Serbia's team for January's ATP Cup in Sydney despite uncertainty over his vaccination status.

To play in Sydney without being vaccinated, the New South Wales state government would have to apply for an exemption for him.

Djokovic would then have to do 14 days of quarantine on arrival.

The record nine-time Australian Open champion has yet to commit to defend his title in Melbourne after organisers confirmed that all players would need to be vaccinated.

Last week, Djokovic's father said that his son was unlikely to play in the opening Grand Slam of the year - which runs from 17-30 January - unless rules were relaxed.

Serbia have been drawn alongside Norway, Chile and Spain in Group A for the season-opening tournament, which will feature 16 teams and be hosted across two venues at the Sydney Olympic Park from 1-9 January.

However, Rafael Nadal will not feature for Spain as he continues his return from injury.

Britain are in Group C alongside Germany, Canada and the United States while defending champions Russia, led by world number two and US Open champion Daniil Medvedev, were grouped with this year's finalists Italy, Austria and hosts Australia.