Nani is keen to carry on with the club, but is not sure whether the club wants to do the same.
The Portuguese star's advisors have been trying to sort out a new contract since the end of last season but without success.
United were ready to hand him an increase on his 90,000 pound-a-week deal that has two years left to run in May, The Sun reports.
United proposed a salary rise of between 30,000 pounds and 40,000 pounds a week, but it is understood his demands exceeded what was on offer.
United immediately called a stop to negotiations despite Nani's advisors then lowering their initial demands.
Nani, on a three-week break after reaching the semi-finals of Euro 2012 , has still not heard anything from the club and he will not be going on the pre-season tour of South Africa and China.
The star now wants his future sorted before the chief executive David Gill, boss Alex Ferguson and the squad fly out in 12 days. (ANI )