Home Secretary Suella Braverman could face a legal challenge over her plan to house migrants on a floating accommodation barge.
Tory-run Dorset Council is opposed to the use of Portland Port as the site, and local Conservative MP Richard Drax was working to get the plan “consigned to the dustbin”.
The Bibby Stockholm vessel, which will reportedly cost taxpayers more than £20,000 a day, could accommodate more than 500 migrants.
Portland Port confirmed it had been selected by the Home Office as a site for a migrant barge, but Dorset Council said it has “serious concerns about the suitability of the location for this facility”.
Details of any agreement with Liverpool-based Bibby Marine Limited and the costs were unclear, but the 93-metre long vessel can house up to 506 people in its 222 bedrooms.
Mr Drax, the South Dorset MP, said the barge was being “dumped on our door” without consultation by the Home Office as he urged Ms Braverman to scrap the idea.
“Every option’s being looked at including legal action,” he told the PA news agency.
“We want to get this consigned to the dustbin before anything’s signed.
“We want to activate ourselves and say look Home Secretary, sorry, this is not the right place, can you please cancel this.”
He raised concerns about the practicality of keeping hundreds of vulnerable individuals in a “very, very restricted area”, placing extra pressure on the port’s “very small” police force.
“They will be allowed out on a bus every so often but in effect will be incarcerated for quite a lot of the time,” he said.
He also raised concerns about the impact on businesses in the seaside resort of Weymouth, adding: “This is an extremely sensitive area which relies heavily on summer trade, I cannot see how this is going to be anything but detrimental. ”
Portland Port said details of the scheme were still being finalised.
The port’s chief executive, Bill Reeves, said: “Portland Port has been selected by the Home Office to provide space for an accommodation facility.
“We are currently liaising with the Home Office about the next steps.”
The company described the Stockholm vessel, which is currently in Italy, as offering “luxury living” with a gym, bar, restaurant and games room.
But immigration minister Robert Jenrick has said that migrants will be housed in “rudimentary” accommodation rather than hotels while asylum claims are processed, meeting “their essential living needs and nothing more”.
Bibby says the three-storey barge has been refurbished since it was described as an “oppressive environment” when the Dutch government used it to house asylum seekers.
A Home Office spokeswoman said: “The pressure on the asylum system has continued to grow and requires us to look at a range of accommodation options which offer better value for money for taxpayers than hotels.”
Plans for other sites to house migrants under the Government’s new policy to curb the use of taxpayer-funded hotels could also end up in the courts.
Conservative-run local authorities have threatened legal action against the Home Office over the proposal to use RAF Scampton in Lincolnshire and RAF Wethersfield in Essex to house thousands of migrants.
The Home Office says new types of accommodation must be used to reduce a £6 million daily bill for using hotels.
Enver Solomon, chief executive of the Refugee Council charity, has described the use of military bases and boats as “wholly inadequate places” to house people who have fled war and persecution.