Liberal Democrats leader Vince Cable believes it would be "tragic" if Millwall were forced to move away from The Den.
The Championship club are facing uncertainty due to an ongoing threat of a compulsory purchase order of land around the stadium by Lewisham council.
Cable, who visited the Lions on Wednesday, says the situation is stopping the club from developing.
"Talking to people from the club it is clear there is a real threat," Cable told Press Association Sport.
"They are really angry about the way the compulsory purchase order is still hanging over them, it's preventing them from developing.
"I didn't know Millwall Football Club very well, they are obviously a great club, they are very community-minded, they want to do things locally, they want to give people a chance in life and they are frustrated if this development goes ahead.
"They have an ambition to get in the Premier League and support the local community.
"There is a very clear warning that if this development goes ahead or the CPO isn't lifted they may have to go somewhere else and that would be tragic and they are very clear that the Labour council, because it is had no opposition, are to blame for this."