Bayern Munich have expressed their irritation at Philipp Lahm going public with his decision to retire at the end of the season, but stressed the defender will always be welcome at the Allianz Arena.

The 33-year-old announced in the wake of the 1-0 DFB-Pokal win over Wolfsburg on Tuesday that he will hang up his boots at the end of the 2016-17 campaign, and has rejected the opportunity to become the club's new sporting director.

Chairman Karl-Heinz Rummenigge did not see Lahm's announcement coming and assumed both parties would make a joint statement, but he insisted the door will always be open to Lahm.

"Bayern Munich are surprised by the approach of Philipp Lahm and his adviser," read a statement from Rummenigge.

"Uli Hoeness and I have held open, intensive and constructive talks with Philipp in recent months about a possible position as sporting director of our club. At the end of last week, he informed us that he is currently not available for such a position and that he would like an early termination of his player contract, which runs until June 2018, at the end of the current season.

"Until Tuesday we assumed that there would be a joint announcement on this decision by Philipp Lahm and Bayern Munich.

"Philipp Lahm has been an important player for Bayern Munich for over a decade. We are convinced that our captain will now concentrate fully with the team on the tough upcoming tasks in the Bundesliga, Champions League and DFB-Pokal. We would like to make clear that the door will always remain open for Philipp at Bayern."

Bayern president Hoeness, meanwhile, said there was no hard feelings despite Lahm's stance.

"The door will always be open to Philipp Lahm. I can imagine him working at Bayern one day," Hoeness told WAZ.

"Philipp deserves our utmost respect.

"We are not disappointed with his decision, just surprised. We were in no rush. He could have started as sporting director as per January 1, 2018. Karl-Heinz Rummenigge outlined what we expected from him."

Hoeness initially refused to confirm whether Lahm would retire when asked about it immediately after the victory over Wolfsburg following a report in Sport Bild, only for Lahm to then go public in the mixed zone shortly after.

"I wanted to stick to what we had agreed and calmly discuss how we would go public first. We were not interested in announcing it this early," Hoeness added.

"But the surprise announcement of his retirement is just a detail and does not change anything. 

"Philipp told Rummenigge about it on Friday. But it makes no sense to go public before important games. We faced Schalke on Saturday, there was a supervisory board meeting on Monday and then the next game on Tuesday. We wanted to discuss our course of action on Wednesday."