As many as 1,000 workers could be living in sheds across Slough
More than 1,000 migrant workers across Slough are thought to be living in sheds in people's back gardens.
Slough Borough Council believes the problem has become so great, it is working with the UK Border Agency and police to ensure tenants' well-being.
Many of the shed-dwellers are living in an estimated 1,000 sheds, especially in Upton, Baylis, Central and Chalvey.
The council said it was clamping down on landlords and reminding them of the planning rules for outhouses.
Many of the buildings are legal and within the size permitted for the gardens they are within, however the majority should not be inhabited.
Housing standards manager, Keith Ford, said the council would fine or prosecute landlords breaking the law.
He said his team would try to re-home the immigrants, many of whom were living in the sheds without proper sanitation and were "being exploited".
"Although in many cases, Slough Borough Council doesn't have a statutory obligation to re-house these people - but we do have a moral obligation," he said.
"We will make temporary housing available for those who aren't eligible for re-housing.
"Ultimately though, it is the responsibility of the landlords themselves to find these people alternative accommodation."
He added the situation was also having a negative impact on the area.
"It causes problems with anti-social behaviour, it obviously puts a strain on the services provided by Slough Borough Council, and it just doesn't look very nice," Mr Ford said.
Slough has a large immigrant population, and at the time of the 2001 census the borough was the most ethnically diverse outside of London.
Christine Hulme, from the Action4Chalvey residents' group, said the problem was causing overcrowding.
She said extra rubbish was becoming an environmental health issue "because of rats".
"There's also congestion in terms of sheer space that people have got, things like parking, traffic," said Ms Hulme.
"And it must also have a burden in terms of local services."
Thames Valley Police said the force dealt regularly with incidents involving the outbuildings, and was "well aware" of people living in them.
"There was a fire in a shed the other day that had someone living in it," a spokeswoman said.
"Luckily, they were pulled to safety.
"It's a council housing issue really, we only deal with such incidents."