The German international is said to be a top target for United manager David Moyes, who is believed to have around £200m to spend on transfers this summer.
Recent reports emerged claiming that the Premier League outfit have opened negotiations with the Bundesliga outfit, and are willing to offer Kroos £260,000 per week.
However, Kroos's representative is adamant that the 24-year-old will honour his Bayern contract until 2015.
"There has not been any official contract offer [from Manchester United]," Struth told Bild. "And there is absolutely no need to table an official bid either because Toni will stay with Bayern Munich at least until 2015."