New rights for temporary workers to 'cost £2bn a year'
1 October 2011 Last updated at 07:31 BST
More than one million temporary workers who live in the UK will now receive the same rights, pay and benefits as full time staff after they have been employed by a company for more than 12 weeks.
Unions and agency workers have welcomed the change, but it could cost businesses up to £2billion a year.
Joe Lynam reports.