The BVB chief is angry with the German champions over their public pursuit of Marco Reus and has cut off ties with the Bavarians
Germany's two top clubs have made attempts to mend their broken relationship in recent months, with the Bavarians' recent deals for Mario Gotze and Robert Lewandowski having created a rift between the pair.
However, Rummenigge has been speaking openly about the possibility of Bayern attempting to lure Marco Reus away from Signal Iduna Park over the past couple of months, much to the annoyance of Watzke.
"Our relationship has been professional for a long time. But at the moment, I believe there's no relationship at all," he told SportBild.
"You shouldn't talk publicly about contractual terms of employees of a competing company to the public, no matter how you say it. And the Bundesliga is no exception.
"Nobody in Germany speculated about whether Toni Kroos was going to Madrid because it wasn't their business ..."
Bayern and Dortmund will renew on-field hostilities at 18:00CET on Wednesday, when they clash in the DFL-Supercup at Signal Iduna Park.