Bundesliga leaders Bayern Munich fired in three goals in the opening 15 minutes en route to a 6-0 demolition of hosts Hoffenheim on Saturday in a game interrupted for 20 minutes over an offensive banner unfurled by visiting fans.

Bayern moved four points clear at the top of the table but the match was at risk of being cut short when the Munich club's fans displayed the banner insulting Hoffenheim investor Dietmar Hopp in the 79th minute.

The referee ordered the teams into the tunnel and some Bayern players as well as the entire club leadership walked to the stands and urged fans to take it down immediately.

After a 20-minute interruption both teams came back onto the pitch and ran down the clock without playing competitively, ending the game with an ovation for Hopp and with Bayern CEO Karl-Heinz Rummenigge by the billionaire's side in a show of solidarity.

Hopp has been a lightning rod for some German fans, who oppose the way he used his wealth to help Hoffenheim climb through the lower leagues to the Bundesliga with consecutive promotions more than a decade ago.

A similar insulting banner led to a Borussia Dortmund fans' ban in Hoffenheim for two seasons and €50,000 fine earlier this month.

"I am deeply ashamed for the behaviour of these people. That is inexcusable. It is the ugly face of football," Rummenigge told reporters.

"I have apologised to Dietmar Hopp. We have filmed everything and these people will be held accountable."

Yet it had gone so smoothly for the champions, who were without injured top scorer Robert Lewandowski.

His absence was not felt when Serge Gnabry volleyed them ahead in the second minute. Joshua Kimmich doubled the advantage five minutes later and Joshua Zirkzee made it 3-0 with a clever turn and shot.

Philippe Coutinho scored once either side of the break and Leon Goretzka completed the rout in the 62nd but Hoffenheim had long thrown in the towel before the game ended on a sour note following the interruption.

Bayern are on 52 points, four ahead of RB Leipzig, who host Bayer Leverkusen on Sunday.

Borussia Dortmund are third on goal difference following their nervous 1-0 victory over Freiburg.