Spanish champions Real Madrid are thought to be leading the chase for the 26-year-old, with Manchester United and Paris St Germain reportedly among other potential suitors.
Quoted in several national newspapers, Villas-Boas said: "There has been continuous interest from three different clubs in Luka. But it is important for Tottenham to hold onto their rights. His situation will continue as it is until the price is right. It's important to understand his feelings. We have been speaking and I understand his point and he understands the club's point."
Modric first stated his desire to leave White Hart Lane last summer after the team failed to qualify for the Champions League. The north London club stood firm, but speculation has been rife again recently after Chelsea's triumph in this year's Champions League final meant Spurs once again missed out on Europe's premier club competition.
Speaking after Wednesday night's 2-0 pre-season friendly win at Stevenage, Villas-Boas added: "Luka is an intelligent person and understands the club has to defend his value their values, rights and interests.
"It's a difficult situation for the club but we have been co-operative by openly saying we are willing to listen to offers.
"But the offer has not been met to what the chairman [Daniel Levy] wants. If that is met there won't be any problems."
Modric, who joined Tottenham from Dinamo Zagreb four years ago, is under contract until 2016.
Source: PA
Source: PA