The data obtained under the Freedom of Information Act revealed 1,270 Notification of Liability (NOL) notices for a civil penalty were issued to UK employers of illegal workers in 2012.
In 2008 the UK Border Agency introduced a civil penalty system, which means enforcement officers can fine employers up to £10,000 for each illegal worker employed.
Giant group said the amount of penalties issued proves there are still many employers and recruiters that are failing to adequately assess an individual's right to work in the UK.
Giant, managing director, Matthew Brown, said: "Compliance and efficient checking of an individual's employability rights have been hot topics over recent months, with more being done to raise awareness of the legal requirements for employers and recruiters.
"However the number of NOL's issued still remains high," Brown said. "As fines are set to rise it's vital the correct processes are implemented to reduce the associated risk on businesses."