Tesla and SpaceX workers should put in 80 to 100 hours a week to "change the world", Elon Musk has said.

The technology entrepreneur admitted that there were "way easier places to work" than his companies, adding: "Nobody ever changed the world on 40 hours a week."

Asked how many hours a week were necessary, Mr Musk said: "Varies per person, but about 80 sustained, peaking above 100 at times. Pain level increases exponentially above 80."

Mr Musk's comments attracted criticism from commentators who suggested that overwork could lead to decreased productivity.

He is the founder and chief executive officer of several companies including SpaceX, which is working on building disposable rockets, Tesla, which designs and builds electric cars and sustainable energy sources, The Boring Company, a subsidiary of SpaceX which is building underground tunnel networks, and Neuralink, which says it aims to "connect humans and computers".