Laws to ensure that the P&O Ferries mass sackings scandal can never recur will be laid before parliament this week as Labour clamps downs on poor working conditions at sea, with cruise and cargo ships also in its sights.

The transport secretary, Louise Haigh, said the new laws would close the loopholes exploited by P&O when it fired 800 crew without warning in 2022, and any company would now face unlimited fines for acting in such a way.

Provisions in the employment rights bill designed for seafarers will toughen laws around collective dismissal. The government will also pass regulations making cross-Channel ferry operators pay the national minimum wage of £11.44 an hour from 1 December under the Seafarers’ Wages Act.

The deputy prime minister, Angela Rayner, said the P&O Ferries scandal was “exactly why we’re taking bold action to improve job security”, adding that the changes would “benefit good employers to compete on quality and innovation, rather than a race to the bottom”.

P&O Ferries, and Irish Ferries before it, had substantially undercut competitors’ staffing costs by using agency workers on low wages.

The government said new measures would end “fire and rehire” practices, except where employers genuinely have no alternative. Although P&O Ferries claimed that its business was unviable without changing its staff structure, Haigh said it was a “rogue operator” while others had continued to employ full-time crew.

She said: “DFDS has continued operating on the Dover straits with decent employment factors and proper pay for their staff. P&O Ferries is owned by a very profitable parent company, and it is highly questionable whether they had to take that step.

“They treated their staff abominably. We are a government that wants to work in partnership with business and the workforce, but not with rogue operators.”

The measures will initially apply to ships that visit UK ports 120 times a year, regardless of whether they sail under a foreign flag or of the crew’s nationality.

Operators that fail to prove they are paying minimum wage will be forced to pay a surcharge when entering ports, and potentially blocked from entry altogether.

Haigh said the government wanted to go further, on both working conditions and the scope of ships, but it was “challenging” with international shipping law, and she wanted the bill to be “ironclad”.

The government was studying the situation in France, she said, which has enforced its minimum wage on cross-Channel ferries since June but faced a legal challenge over some regulations.

Most cargo and cruise ships will not be affected by the new laws because they spend more time in international waters. However, Haigh said: “There’s no operator that should be applying poorer conditions on sea than at land. We saw some of the cruise ships attempting similar fire and rehire just last year, we know these practices are commonplace on ferries and cruises. We want to make sure that we get to the bottom of the exploitation of workers in our waters, and make sure that their conditions are protected.”

Gemma Griffin, vice-president of global crewing at ferry operator DFDS, whose ships are flagged in the UK and France with fully employed crew earning more than minimum wage, welcomed the news: “It means we can continue to ensure our colleagues are protected. And it goes some way to restoring the level playing field in the Dover Straits.”

Speaking on board the DFDS Dover Seaways ferry, Captain Adrian Sheaff said: “The exploitation of seafarers isn’t a conversation that in this day and age should happen. I hope that this is aimed at ships flying under flags of convenience that are party to the maritime labour convention but don’t meet its standards.”

The seafarers unions Nautilus and RMT welcomed the move. Both are pushing for a mandatory charter that could also limit working hours and enforce regular crew rotations, with ferry crew traditionally working for no more than two weeks at a time at sea prior to the P&O sackings.

The RMT general secretary, Mick Lynch, said it showed Labour was “serious about protecting seafarer jobs” and that action was “long overdue”.

Martyn Gray of Nautilus said: “We have confidence that the government is committed, they’ve made a really strong start and we think that where they can do more, they will.”

A spokesperson for P&O Ferries, which is owned by DP World, said: “P&O Ferries always complies with all relevant national and international laws, and as such we have made changes to our crewing policies to meet new legal requirements.”

It said it had revised crew rotations as directed by French legislation which meant it was “no longer practical to employ crew from outside Europe in large numbers, due to travel time and the requirements of the immigration system”.

A spokesperson for the separate, Carnival-owned, P&O Cruises said: “Our seafarers are, and always have been, at the heart of our business. We will not be dismissing and re-engaging any of our crew members.”