The Bundesliga champions have declared that the Polish duo are not for sale and stated that they are focused on strengthening their squad
The Polish duo have reportedly garnered interest from a host of clubs across Europe after helping Dortmund win their second successive Bundesliga title.
Real Madrid are understood to be one of the sides interested in Piszczek, but Watzke insists that not even the prospect of a big-money sale will make the club part company with their prized assets.
"You can save yourselves the trouble of making an offer for Piszczek or Lewandowski," he is quoted by EFE as saying.
"We will not sell them for all the money in the world. We do not want to compete with banks, but to have a strong team."
Piszczek, who arrived at Dortmund in 2010, has a contract with the club until 2016, while Lewandowski has two years left on his deal.