On the eve of their Bundesliga showdown, Bayern Munich chairman Karl-Heinz Rummenigge has insisted his club are not trying to weaken rivals Borussia Dortmund by attempting to sign Marco Reus.

Bayern host Dortmund at Munich's Allianz Arena on Saturday with Borussia having finished second to the Bavarians for the last two seasons.

But Dortmund currently lag 14 points behind leaders Bayern and are 15th in the table after four consecutive defeats -- one of the worst starts to a league season in the club's history.

And there is also bad blood between the clubs' senior bosses.

Bayern have signed stars Mario Goetze and Robert Lewandowski from Dortmund in the last two years and Rummenigge had stirred further tensions by revealing Borussia's Germany winger Reus is their next target.

He has drawn attention to the release clause in Reus's Dortmund contract, which runs until 2017, but Rummenigge insists Bayern are not out to weaken Dortmund's squad.

"We don't have to weaken anybody. Every transfer has exclusively one goal: to strengthen the team's quality," Rummenigge wrote in Saturday's match programme.

Rummenigge also pointed out that if Bayern signed Reus they would only be copying the actions of Dortmund, who signed the 25-year-old from Borussia Moenchengladbach at the end of the 2011/12 season by activating his buy-out clause.

Dortmund chief executive Hans-Joachim Watzke has made his feelings clear about Rummenigge's interest in Reus, while the player has said his only priority currently is to leave Munich with three points for Dortmund.

"There was simply no need for him to have said anything, but that is not his style," said Watzke.

Traditionally, senior figures from the rival teams dine together before a Bundesliga match, but that will not be the case on Saturday.

"There is no invitation, so I don't have to turn it down," revealed Watzke.

"We don't have any sort of relationship and we don't have to. He's responsible for Bayern Munich, as I am for Dortmund. So there is nothing we have to do together."

Watzke said he preferred dealing with Bayern's former president Uli Hoeness, who is currently serving a three-and-a-half-year prison sentence for tax evasion.

"I always had a very exciting relationship with Uli Hoeness, who I really miss, because he was someone who came at you straight on and with an open visor," said Watzke.

"You could argue with him, but you always knew where you stood with him -- that's something I personally always really liked."