Melbourne, Jan 10 - Roger Federer Sunday declined to play the AAMI Classic Australian Open tune-up event, with the late decision opening possible doors for the likes of rivals Andy Murray and Andy Roddick.

The Swiss, who lost to Nikolay Davydenko in the Doha semi-finals, had a place reserved in the eight-man field in Melbourne at the round-robin event considered the prime preparation for the Open from next Monday.

But Wednesday's start at Kooyong club, one-time home of the Grand Slam until just over two decades ago, now means that an eighth man must be chosen to make up the numbers.

Federer's management telephoned promoter Colin Stubs Sunday morning with the news that their man will use next week for private practise.

Stubs had been holding a place for Federer in the field, but will likely be spoiled for choice in exactly how to fill it. The choice will be announced Tuesday, one day before the start of the four-day special event.

Four players have already arrived: Novak Djokovic, Robin Soderling, Fernando Gonzalez and Tommy Haas.

2008 Australian Open champion Djokovic and Soderling, the French Open finalist against Federer last June, have both put in heavy practise sessions at Kooyong over the past two days.

On their way to Melbourne are US Open winner Juan Del Potro, Jo-Wilfried Tsonga and Spain's Fernando Verdasco.

Murray and Roddick have put in quiet bids for spots the field, with Murray considering asking for a practise match only.

Logistics could be complicated as 2008 Open finalist Tsonga battles a wrist injury which has forced him from two events already in the New Year. (dpa)