Immigration tip-offs 'not sufficiently detailed'
8 November 2013 Last updated at 16:11 GMT
Only 6% of tip-offs about illegal immigrants are investigated and 1.5% result in deportation - the Home Affairs Select Committee has found.
The Home Office says not all allegations are true and some cases do not contain enough information to enable action to be taken.
Lucy Moreton, General Secretary of the Immigration Services Union told BBC Radio 5 live's Tony Livesey: "Wherever you have an anonymous line... there's going to be an element that's not sufficiently detailed and there's going to be an element of malicious allegations being made."
However Habib Rahman, Chief Executive of the Joint Council for the Welfare of Immigrants, claimed than an increase in surveillance would create a "snooping and sneaking culture... leading to racial profiling."