Bayern Munich coach Jupp Heynckes has rejected advice from German legend Franz Beckenbauer to ring Pep Guardiola and glean some tips for its Champions League semi-final against Barcelona.

"I don't understand how a former player and coach can say that," said Heynckes ahead of Bayern's German Cup semifinal against Wolfsburg on Tuesday, with his team bidding to become the first German side to win the treble.

"Maybe I should ring Johan Cruyff, after all he instigated the Barcelona system," he said.