Photographs showed around 100 Cologne supporters sitting down on the road to the stadium in a protest against Leipzig which is bank-rolled by energy drinks manufacturer Red Bull.
The bus eventually reached the stadium via an alternative route although it could not enter the underground car park, causing further problems for the visitors, German media said.
"We had a bit of trouble getting to the stadium and we needed more time to prepare professionally for the match," Leipzig coach Ralph Hasenhuettl told reporters.
Founded in 2009, Leipzig quickly moved up from the fifth tier to the second by 2014 after winning promotion three times in five seasons.
They won promotion again last season to reach the Bundesliga for the first time.
Rival fans say Leipzig are an example of a "plastic club" -- which has no genuine fanbase and owes its existence to financial support from wealthy backers.
Under German football rules they cannot be called Red Bull Leipzig and are officially known as RasenBallsport Leipzig (grassball sport Leipzig) or RB Leipzig.
Leipzig have been greeted by protests at other grounds over the last two years and fans of local rivals Dynamo Dresden dumped a severed bull's head on the pitchside during cup match last month.
(Writing by Brian Homewood, editing by Pritha Sarkar)
