Sky TV chief executive Martin Stewart is leaving the company, after less than two years in the job.

Chief commercial officer Sophie Moloney will take over the role immediately, becoming the company's first female CEO.

Chairman Philip Bowman says Martin Stewart will stay with the company for another three months, before returning home to Europe.

He says the company has faced an exceptionally challenging year -- but is in a good position to expand its streaming and broadband services, and secure rights to more entertainment and sport.

Stewart became chief executive in February last year.

Sky shares closed at 17c yesterday. The stock is down 63 per cent for the year.