The news comes just over a year after the disgraced company unlawfully sacked 800 seafarers.
RMT General Secretary Mick Lynch said: “This is another shameful chapter in the history of P&O Ferries where yet again they show scant regard for the livelihoods of their workforce.
"Another 60 job losses comes on the back of introducing new vessels to its fleet at a cost of over £200m.
"Over the past 12 months this company has demonstrated no loyalty or commitment to its workforce or local economies in the ports in which they operate whilst jeopardising the safety of travelling passengers.
“The government should immediately strip P&O ferries and their parent company of any right to operate from UK Ports.
"This government has failed to hold P&O Ferries to account and as such Peter Hebblethwaite and those at DP World continue to cause destruction in the UK maritime sector.
"RMT continues to campaign for fair pay agreements, an end to discrimination and real sanctions against P&O Ferries that will deliver the decent jobs and skills our maritime communities need."