David Cameron has insisted he can meet his target to reduce net migration to the tens of thousands despite new figures showing the number had soared.
Figures showed net-migration rose to 318,000 last year - the highest figure since 2005.
After announcing new plans to cut immigration, Mr Cameron told ITV News' Romilly Weeks that he would not abandon his target, saying the figures showed "how much work we have to do".
Taking illegal workers' wages will make lives "more difficult" and would not help control immigration, a campaign group has warned.
"Confiscating wages, making people's lives more difficult is not the answer," Saira Grant, from the Joint Council for the Welfare of Immigrants, told Good Morning Britain.
She also questioned the practicalities of the measure, particularly when taking the wages of people working cash-in-hand in low-paid work.
Earlier, Home Secretary Theresa May insisted the plan was "only fair" to British workers.
Make no mistake, these fresh net migration figures are absolutely terrible for the Government.
David Cameron will unveil plans later today for "radical" new laws to control immigration that include seizing the wages of illegal workers.