Thousands of tennis fans have rolled into Melbourne Park for the first day of action at the Australian Open.

Lleyton Hewitt and Samantha Stosur are among Australians in action on day one, while international stars on show include defending men’s champ Novak Djokovic and second seed Maria Sharapova.

As crowds swelled behind the entry gates ahead of the 10am (AEDT) Monday opening, former champs Sweden’s Mats Wilander and the USA’s Lindsay Davenport paraded the winning men’s and women’s trophies, and declared their love for the tournament colloquially known as “the happy slam”.

“It’s just a really fun tournament, everybody’s excited, everybody wants a good start to the year, some of them are full of confidence, and Australian people are sports crazy,” Wilander told reporters.

“It’s the most friendly to all the players and they love playing here, they love the fact that they really feel appreciated playing here by not only the Australian public but also by the tournament (staff),” Davenport said.

Both tipped favourites defending champ Novak Djokovic and five-time winner Serena Williams to win this year’s open.

Officially opening the fortnight-long tournament, Victorian Premier Ted Baillieu said he hoped the crowd would top last year’s 686,000 attendees.

He said Melbourne Park’s $366 million stage one redevelopment was on show, which includes the new 21-court National Tennis Centre, adjacent public and entertainment plaza, more elevated viewing decks and upgraded entries to Hisense Arena.

“The courts are ready, the players are ready, the tournament organisers are ready, the umpires are ready, the ball boys are ready, and we are absolutely delighted,” he told the crowd.

With an estimated 300 million worldwide viewers, Mr Baillieu said the tournament will create more than 1400 jobs and inject an estimated $239 million into the Victorian economy, with hotels, restaurants, retailers and tourist attractions all set to reap benefits from an influx of international tennis fans.