Giant-killers Kaiserslautern aim to take a leaf out of Borussia Dortmund's book in their bid to claim a shock German Cup semi-final win at holders Bayern Munich on Wednesday.

Dortmund stunned Bayern 3-0 at Munich's Allianz Arena in the league last Saturday as the European champions suffered their first Bundesliga home defeat since October 2012.

Second division Kaiserslautern, who earned an upset quarter-final victory at Champions League side Bayer Leverkusen and beat Hertha Berlin in the second round, have not won in Munich for 17 years.

"Kick it like Dortmund and everything will be OK. If only it was that simple," said Kaiserslautern coach Kosta Runjaic when asked if Dortmund's victory in Munich gave cause for hope.

"We have to be realistic. Bayern are the best side in the world, they are powerful and the game is theirs to lose.

"We have only a minimal chance, but we will try to take it."

However, it wasn't all doom and gloom from Runjaic.

"We also represent a big club and we're not just going to Munich to swap shirts," he added.

"We won't approach the game with fear, but with fun and determination."

Despite Runjaic's heavy dose of realism, Bayern are vulnerable and winless in their last three league games, including defeats to Dortmund, Bavarian neighbours Augsburg and a 3-3 draw at home to Hoffenheim.

Bayern could also be without Germany goalkeeper Manuel Neuer, who suffered a calf injury in Saturday's 3-0 defeat at home to Dortmund.

"If the game was yesterday, he couldn't have played. Same today, I hope he can play tomorrow," said Bayern coach Pep Guardiola on Tuesday.

If Neuer fails to play, the 20-year-old Lukas Raeder will deputise, having conceded a goal just three minutes into his Bundesliga debut against Borussia.

The 'Red Devils' of Kaiserslautern were drubbed 4-0 by Bayern in Munich in last season's second round of the cup when the Bavarian giants fielded a weakened side.

The semi-final tie also demonstrates the 'haves' and 'have nots' of German football.

The four million euros ($5.5 million) Kaiserslautern will earn from the German Football Association (DFB) for making the semi-finals will help reduce the club's financial losses for the season to under a million euros.

In contrast, Bayern can expect to make in excess of 50 million euros for reaching the semi-finals of the Champions League, where they will face Real Madrid, the first leg taking place in Spain on April 23.

"Thanks to the cup, we can limit the damage," said Kaiserslautern's chairman Stefan Kuntz.

Dortmund host VfL Wolfsburg in Tuesday's other semi ahead of the final at Berlin's Olympic Stadium on May 17.