The Polish striker, who was speaking after Bayern's final game of the Bundesliga season, a 2-2 draw with VfL Wolfsburg, still has a year remaining on his current deal but there have been widespread reports that he is keen for a move this summer.
"I can confirm that I spoke to Hasan [Salihamidzic, Bayern sporting director] and informed him that the decision was made -- and that I am not extending my contract with FC Bayern," he told Sky Germany. "Both sides have to think about the future. It's best if we find the best solution for both sides.
"I said to [Salihamidzic] that if an offer comes, then we have to think about it -- also for the club. Both sides have to think about the future. That's all I can say.
"I still have a year's contract [left at Bayern]. But I said that we have to find the best solution for both sides. We'll have to wait and see what happens."
Speaking before Saturday's game, Salihamidzic suggested that they could keep the Bundesliga's second-highest all-time scorer until the end of his contract despite being informed he is eager to leave.
"I spoke with Lewa. In that discussion he informed me that he does not want to accept our offer to extend the contract and that he would like to leave the club," Salihamidzic told Sky Germany.
"He said he wants to do something else. But our position has not changed. The fact is he has a contract to June 30, 2023."
The 33-year-old joined in 2014 from Borussia Dortmund on a free transfer and has won the Bundesliga title every year since then, as well as the Champions League.
Barcelona have been strongly linked as one destination for Lewandowski and speaking earlier on Saturday, Barca coach Xavi Hernandez did not dismiss their chances of landing the striker.
"I signed Dani Alves at 38," Xavi said when asked about his attitude towards more experienced signings. "It isn't about age, it's about performance. Players look after themselves so much and every year they're more professional.
"[Zlatan] Ibrahimovic, [Luka Modric], Alves... They've all performed very well at important clubs. Cristiano [Ronaldo] and [Lionel] Messi too. Age isn't a priority. If they improve us, that's what's important."