Transport Secretary Grant Shapps said the boss of P&O Ferries should quit for his “brazen, breath-taking arrogance” in admitting breaking the law over a mass sacking.
The cabinet minister also said he would change legislation to force a U-turn and prevent the ferry operator from paying a minimum wage to its employees, according to the Sky News.
Later, asked by the BBC if Boris Johnson supported Shapps' call, a No 10 spokesman said: "Yes."
The comments come after P&O chief executive Peter Hebblethwaite admitted to MPs that the company had breached employment law when it abruptly fired 800 workers.
The company didn’t consult with unions as it knew they wouldn’t approve of the job cuts, he told the Commons transport committee.
The comments from Shapps come after the chair of the transport committee said Hebblethwaite should consider his position.
Hebblethwaite on Thursday also disclosed he receives a £325,000 base salary, is in contention for two bonus schemes and hasn’t decided whether to accept.