Dredging at freeport sites across the UK should be paused while a mass die-off of marine life is investigated, ministers have been told.

MPs used a Commons questions session to express further concerns over the deaths of thousands of crabs and lobsters washed up on North Sea beaches.

The Government said it expects to receive a report from an independent panel of experts this month, adding it will “respond to the facts as they are presented”.

The mass die-off of marine life on the coastline from Hartlepool to Whitby saw crustaceans washed ashore between October and December 2021, with dying creatures “twitching” and displaying lethargic behaviour.

The Department for Environment, Food and Rural Affairs (Defra) last year said it had concluded that “a naturally occurring harmful algal bloom” was the most likely cause of the deaths, after a “thorough investigation”.

But subsequent research by academics, backed by the fishing industry, suggested the incident could have been caused by industrial pollutant pyridine, possibly from dredging in the mouth of the River Tees to maintain channels for port traffic.

Teesside is home to one of the Government-backed freeports – special economic zones offering tax breaks and lower tariffs.

Speaking in the Commons, Labour MP Ian Byrne (Liverpool West Derby) said: “Following the environmental catastrophe and mass die-off of marine life in the North Sea off Teesside, and while we await the hopefully independent panel’s findings about the causes of this disaster that has devastated the ecosystem and ruined livelihoods, will the minister confirm whether capital dredging for the Teesside freeport project, and at other freeports including Liverpool, will be paused while the Government awaits the panel’s findings?”

Environment minister Mark Spencer responded: “I think it is very important we get the facts as soon as possible but I want to give that independent panel time to assess the actual facts that we are faced with.

“He and I share the ambition, we want to know the facts of what is causing that die-off in the North East. We want them to look at that independently without pressure and then as soon as we have those facts we can then respond appropriately.”

Shadow environment minister Alex Sobel said: “I just want the minister – and I thank him for his initial answer – to confirm the independent panel has now been set up and, just because he was very quick in his answer, that they would be reporting this month.

“Because the fishing industry in the Tees is dying off, they need that report and they need that certainty to continue.”

Mr Spencer replied: “The report will be given to the Secretary of State. I expect that report to come this month, as in January. We want to get those facts as soon as possible. We want to respond to the facts as they are presented.”

Earlier, Labour MP Geraint Davies (Swansea West) used a question on food security to say: “Newcastle University believes the mass killing of crabs, lobsters and other crustaceans off the North East is due to dredging ahead of the freeport.

“But Defra has dismissed this as a natural event due to algae blooms, set up an inquiry which was the set-up of a secret panel meeting in private, despite the fact that the Efra (Environment, Food and Rural Affairs) Committee has asked for an open, transparent inquiry that’s done independently.

“Will she now commit to an independent evaluation of the evidence to protect all our coasts from the massive destruction from toxic emissions ahead of freeports from dredging?”

Environment Secretary Therese Coffey said: “I have already replied to the Defra select committee about this. In terms of the impact on crabs, it is under investigation, as he’s aware.

“It makes no difference to the adequacy of the UK’s food security, which indeed is the topic of this question.”