Toto Wolff is "trying to create tension with words" by playing up the chances of Mercedes' rivals ahead of the 2021 season.
"Red Bull already had the fastest car at the end of last year, which is why for 2021, with drivers of this calibre, they are among the favourites."
Wolff also warned that Aston Martin could do a better job than Mercedes in adjusting to the new floor regulations.
When asked about those comments, Marko told f1-insider.com: "At the moment there is no driving, so he is trying to create tension with words.
"We hope to be among the frontrunners, but Mercedes is the clear favourite. They have won every title in the hybrid era since 2014."
As for Aston Martin, Marko added: "I can't imagine that Aston Martin has a completely different rear end than the Mercedes. The past has taught us that."
Marko also played down Wolff's fears that Portimao, slated to host round three of the calendar in early May, may not be able to host its race due to the covid situation in Portugal.
"In contrast to other reports, I have information that the Portuguese GP will take place," he said.