BBCReform UK could take the government to court to prevent migrants being housed in areas where it now controls the local council, party chairman Zia Yusuf told the BBC.
Yusuf said his party had pledged to "resist" housing asylum seekers in Reform-controlled areas and it would use "every instrument of power available", including judicial reviews, to fulfil its pledge.
The Home Office is responsible for housing adult asylum seekers and while councils can object, they have little power to stop it.
Reform gained more than 600 seats and took control of 10 local authorities in Thursday's local elections.
Asked how Reform could fulfil its pledge to voters, given that contracts to house asylum seekers in hotels were drawn up between the Home Office and accommodation providers, Yusuf said the party was "realistic" about the challenge.
"The levers of power at a local level pale in comparison to the levers of power at Westminster," he told the BBC's Sunday with Laura Kuenssberg programme.
But he said "those levers of power will be pulled with all our might by Reform councillors," adding: "There are things you can do, there are judicial reviews, there are injunctions... things around planning, budget allocation."
He told Laura Kuenssberg: "A lot of these hotels... you suddenly turn them into something else which is essentially a hostel that falls foul of any number of regulations - that's what our teams of lawyers are exploring at the moment."
Asked if Reform UK's policy was to house migrants in tents, as the party's newly elected Greater Lincolnshire mayor Dame Andrea Jenkyns suggested, Yusuf said: "That's what France does."
He added: "We will be publishing a plan to deport everybody who is currently in this country illegally in our first term of government.
"We will publish that plan in the coming weeks and you'll see the full detail."
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