Labour has urged companies to “do their bit” to ensure they recruit more workers from the UK.
Shadow immigration minister Chris Bryant said training had to improve, with “unscrupulous” employers being prevented from taking on and exploiting people from poorer countries en masse.
But Mr Bryant was forced to tone down criticisms of Tesco and Next’s recruitment policies, after complaints.
The coalition said Labour was “badly confused” and lacking credibility.
Immigration in the UK has been in the headlines recently, with the government blaming its predecessor for failing to control numbers while in power from 1997 to 2010.