Protesters have blockaded P&O’s ferry terminal after the firm last month sacked 800 workers.
The company came under fire after making the decision to fire staff without notice, with workers told via a pre-recorded video.
P&O Ferries claimed that the business was no longer ‘viable’, and that without major changes, it would fold.
But the move was widely condemned, with First Minister Nicola Sturgeon describing it as “appalling”.
On Friday, blockades were put in place at Cairnryan Port and at Larne Port, with unions joining former P&O workers in protest against the company.
A Police Service of Northern Ireland spokesperson said that around 40 people took part in the action.
“Police received a report of a small protest at approximately 2pm today, Friday April 29, at Larne Harbour,” they said.
“Approximately 40 people were in attendance. The protest ended and no issues were reported.”
Darren Procter, from the RMT union, said that workers are ramping up protests over safety concerns.
“With the events of this week and the European Causeway, it’s something that we as a union have identified is going to be a problem, and it was a problem this week so we decided to have a blockade in Cairnryan and also in Larne,” he said.
“This is something we’ll be looking to do more and more because we don’t believe those vessels are safe, we’re not happy with what P&O have done to the workforce and the impact that it has had.
“Just because the individuals have been sacked and have received the money, it is not the end of the issue.”