Mercedes' future in motor racing has been the subject of recent speculation, after it announced its impending withdrawal from DTM and decision to join Formula E from 2019.
Speaking at the Frankfurt Motor Show, Zetsche said: "Formula one is linked to our history and our brand.
"It is a component that has helped us develop the brand and make it younger, so for now I do not see a change of strategy until 2021. The Concorde agreement will last until that date and I am not even thinking about it," he added.
Zetsche was speaking after Mercedes launched the $5 million Project One supercar, featuring a 1000hp hybrid F1 engine.
"We decided to leave DTM and start the project in Formula E," he explained. "At the moment this series is a social and PR platform, but we want to help to increase the competition between the teams."