Labour has been accused of trying to "bury the truth" about asylum accommodation by refusing to say how nearly £122million has been allocated to local councils.
Conservatives warn the "secrecy is unacceptable" when council budgets are "buckling" and taxpayers face higher bills.
Newly appointed Home Secretary Shabana Mahmood has been challenged to come clean about how the cash is allocated amid fears councils are being "short-changed".
Shadow communities minister David Simmonds warns her in a letter: "This lack of transparency is deeply concerning. Local authorities are facing acute financial pressures as a direct result of asylum accommodation costs, while illegal migration across the Channel continues to get to record levels due to the Labour Government's failure to tackle illegal migration.
"Without clarity on how grant funding is being allocated, taxpayers cannot be confident they are receiving fair treatment. My own [Hillingdon] council estimates it is being short-changed by around £17million, costs which ultimately fall on residents through higher council tax bills."
Shadow Home Secretary Chris Philp warned: "Labour are turning every corner of Britain into a dumping ground for their asylum crisis. People who have lived in the same street for decades now wake up to find their community overwhelmed overnight, with services stretched and safety put at risk.
"Local voices are ignored, objections brushed aside, and families left powerless. This is an immigration crisis, and the feeble Labour government is making it worse".