Viduka, whose late-season goal rush enabled The Whites to avoid relegation from the Premiership, is believed to be unhappy about the number of departures from Elland Road.
The Aussie international striker dropped his bombshell during clear-the-air talks at the weekend with manager Peter Reid.
His agent Andrea D'Amico said: "I'm trying to find an option, which is good for both the club and player ''.
"There is still a lot of work to do before we can close a deal but I'm always working hard and talking to people.
"I hope we can announce something soon. Mark is a top player and it's important that he's playing at a top club next season.''
Viduka is the highest earning player at Leeds with three years left on a £40k-a-week deal.
Leeds would want at least £15m but that will not deter Premiership rivals Chelsea who have money to burn following the arrival of owner Roman Abramovich.
Viduka was taken off to avoid being sent off when he lost his cool in a pre-season friendly at York City and on Sunday he was substituted at half-time in the 4-2 friendly defeat at Burnley.
Afterwards Reid read the riot act and only Alan Smith was spared the manager's criticism.
Viduka's departure would leave Smith as the only international striker on the books.
However, Reid will also be seeking the go-ahead to re-invest money from Viduka's sale in the team.
However, Reid will also be seeking the go-ahead to re-invest money from Viduka's sale in the team.