In a speech to be delivered next week and obtained by The Sunday Times newspaper, Trevor Phillips, chairman of the Commission for Racial Equality, says Britain may be "sleepwalking" into segregation.
He is to warn that a parallel would be the serious ethnic divisions in parts of the United States shown up by the impact of Hurricane Katrina.
"The fact is we are a society which, almost without noticing it, is becoming more divided by race and religion," Phillips says in his speech, to be delivered in Manchester, northwest England, on Thursday.
"Our ordinary schools... are becoming more exclusive and our universities are starting to become colour-coded with virtual 'whites keep out' signs in some urban institutions."
The speech continues: "If you look closely at the campuses of some of our most distinguished universities you can pick out the invisible 'no blacks may enter' message."
Phillips is to propose measures to address the problem, which could include forcing predominantly white schools to take larger numbers of ethnic minority pupils to aid integration.
The speech is to assess race relations in Britain following the 7 July London bombings, which killed 52 civilians and four bombers, all British Muslims, three of Pakistani ethnic origin.
"The fact is we are a society which, almost without noticing it, is becoming more divided by race and religion"
Trevor Phillips, chairman, Commission for Racial Equality
Following the blasts, a series of commentators warned that some British Muslim communities were failing to integrate fully.
According to data cited by The Sunday Times, the number of Britons of Pakistani heritage living in ghettos - defined as areas with more than two-thirds of any one ethnicity - trebled between 1991 and 2001.
Some areas are on their way to becoming "literal black holes into which nobody goes without fear and trepidation and from which nobody ever escapes undamaged", Phillips is to warn.
This risks ending in a "New Orleans-style Britain of passively coexisting ethnic and religious communities, eyeing each other over the fences of our differences".