The Hinwil-based outfit said in a brief statement on Monday that Smith had decided to go back to the UK for family reasons.

"He has already left the company," read the statement. "We would like to thank Mark for his efforts and we wish him all the best for his future."

Smith, a former technical boss at Red Bull and Caterham, had joined Sauber in July last year.

He had returned to F1 for the first time since the Caterham team folded in 2014.

Sauber did not provide any information about Smith's replacement.