Shadow immigration minister Chris Bryant has described Tesco and Next as "unscrupulous employers whose only interest seems to be finding labour as cheaply as possible".

He accused companies of operating policies that "seem to deliberately exclude British people".

In an extract from a speech seen by the Sunday Telegraph, Bryant accuses Tesco and Next of hiring foreign workers on lower rates than British staff.

The Labour Party is continuing the latest immigration row, which has led to criticism of Conservative ministers after the Home Office sent out vans with posters challenging illegal immigrants to "go home or face arrest".

Bryant intends to go on the offensive. He will accuse Home Secretary Theresa May of using "gimmicks", and large firms of "exploiting migrant workers" as well as making it impossible for "settled workers in Britain" to compete.

Tesco's revenues are the third highest of any retail company in the world. It employs more than 290,000 people.

A Tesco spokesperson defended the company, saying: "It is wrong to accuse Tesco of this. We work incredibly hard to recruit from the local area, and have just recruited 350 local people to work in our Dagenham site."

In a keynote speech on Monday, Bryant will talk about employers who "recruit workers in large numbers in low-wage countries in the EU, bring them to the UK, charge the costs of their travel and their sub-standard accommodation against their wages and still do not even meet the national minimum wage".

Bryant has also cited firms such as Next for targeting cheap labour by using advertisements printed in Polish.

In an extract from his speech, he says: "Look at Next Plc, who last year brought 500 Polish workers to work in their South Elmsall warehouse for their summer sale and another 300 this summer.

"They were recruited in Poland and charged £50 to find them accommodation. The advantage to Next? They get to avoid Agency Workers Regulations, which apply after a candidate has been employed for over 12 weeks, so Polish temps end up considerably cheaper than the local workforce, which includes many former Next employees."

The shadow immigration minister also shamed the tourist industry. "I have heard horror tales of hotel managements deliberately cutting hours of young British workers and adding hours to migrant workers who do not complain about deductions from earnings that almost certainly take people below the minimum wage.

Labour has said it would double the fines for firms that breach minimum-wage rules.