(AFP) - The German Football Association (DFB) has opened disciplinary proceedings against Bayer Leverkusen coach Roger Schmidt after he refused to leave the touchline during his side's 0-1 home loss to Borussia Dortmund on Sunday.

"It is the normal procedure and there will certainly be a punishment although I can't say what," Anton Nachreiner, the president of the DFB's control committee, told television station Sport1.

Schmidt became engaged in an angry exchange with referee Felix Zwayer following Pierre-Emerick Aubameyang's 64th-minute goal at the Bayrena that gave Dortmund victory.

He was ordered to the stands but refused to leave the technical area, and Zwayer reacted by stopping play and walking off the pitch with his assistants.

The match eventually restarted nine minutes later when Schmidt accepted the referee's decision.

The 48-year-old was furious that Dortmund were allowed to take a quick free kick in the build-up to Aubameyang's goal, but he later apologised.

"I made a mistake that hurt my team," Schmidt said later, but Leverkusen sporting director Rudi Voeller hit out at the referee.

"To interrupt the match like that and cause such confusion was not necessary," the former Germany striker told Sky.

"A referee can be sent to the stands but he needs to be told the reason why, and this was not done." Herbert Fandel, the DFB's head of referees, insisted that Zwayer made the correct decision and said that "in no circumstances can a coach ignore that decision."