Novak Djokovic's charitable foundation has donated $20,000 to Melbourne City Mission's early childhood education program to help disadvantaged children.

The money will go towards the mission's early years supported playgroup program, based in the outer suburbs of Braybrook and Doreen.

A day after his win at the Australian Open, the 28-year-old, who has a 15-month-old son, happily played with children during a visit to the Braybrook centre, signing autographs and even going outside for a hit of tennis.

Later, he spoke to staff and congratulated them on the work they did.

"Early childhood education gives children a chance to respond strongly to any challenge and become winners in any field," Djokovic said in an earlier statement.

"Melbourne City Mission is a leader in providing innovative and effective early childhood programs, and we're very happy to contribute towards their work in this area."

Melbourne City Mission interim chief executive Liz Bishop said the funding would help the organisation provide a safe, stable and enjoyable environment for children.

Djokovic said early childhood learning helped kids respond to challenges in life.

"Early support for children and their families who are experiencing poverty, homelessness, social and cultural disconnection, serious health issues or other disadvantages makes the biggest difference to a child's long-term opportunities in their school years and later life," she said.

"We rely on the generosity of donations such as this, in order to be able to offer families this vital support.

"We thank the Novak Djokovic Foundation for its support, and for its worldwide commitment to early childhood education."

The Novak Djokovic Foundation was created in 2007 with the aim of investing in early childhood development programs.

It said while its main focus was in Djokovic's home of Serbia, work was also carried out internationally.

The world number one also has links with UNICEF.