According to data from The Home Office, a new penalty system introduced in February 2008 led to 233 prosecutions that year - compared with 38 in 2007 and 11 in 2006.
Matthew Brown, managing director of outsourced solutions provider Giant Precision, said: "The new civil penalty for employers who hire illegal immigrants has made a big difference to the UK Border Agency's activity in bringing cases against employers.
"More employers than ever before are finding themselves hit with big fines. In cases where an illegal immigrant is supplied by a staffing agency, the agency itself can be liable."
Many illegal immigrants have been given fraudulent P45s, P60s and passports.
Brown added: "The new civil penalty introduced last year for hiring illegal immigrants has led to new compliance requirements that many recruiters and employers are not set up to handle. Paper-based systems where recruiters or employers photocopy and check documents manually are laborious and prone to error.
"Recruiters and employers can no longer afford to conduct background-checking in a haphazard way. Robust online systems that are thorough can save huge amounts of back office time - and potentially thousands in fines."
Rising number of prosecutions for hiring illegal immigrants make background checks a must
Employers have been warned to undertake more rigorous checks into candidates' backgrounds after new research revealed the number of prosecutions for employers hiring illegal immigrants increased by 513% in 2008.
