According to the quarterly 'Labour Market Outlook' survey published by the Chartered Institute of Personnel and Development (CIPD) and management consultancy KPMG, some 45% of the 600 employers questioned indicated that they had vacancies they were finding hard to fill and, as a result, many were looking overseas to address the situation.

Gerwyn Davies, the CIPD's policy advisor and report author, warned: "The study highlights the complex juggling act the government now faces. The proposed introduction of a migration cap comes at a time when many employers are still struggling to fill skilled vacancies – despite the high unemployment rate."

The training of local workers to fill 'shortage' posts would not happen overnight and even if it did, there was still no guarantee that individuals would pursue a further career in that area as was shown with engineers, he added.

"If a cap is introduced, therefore, it has to be gradually phased in to avoid harming UK competitiveness. Employers running global operations will be forced to offshore skilled jobs to other countries if the right skills mix in the UK cannot be found," Davies said.

The study indicated that 21% of employers had hired migrants over the last three months, with 37% of such workers coming from outside of the European Economic Area (EEA). A further 17% planned to do so during the third quarter of this year.

Some 21% said they intended to hire migrants for engineering posts and 18% for both IT and accountancy/finance positions. Over the last quarter, more than half of migrant workers hired by the financial services sector came from outside the EEA.

Almost one in 10 private sector organisations also planned to offshore jobs in the 12 months to June 2011. Just under two thirds saw India as their favoured offshore destination, with 36% preferring China and just below three out of 10 opting for Eastern Europe. The most popular functions to be outsourced were call centres (55%), IT (51%) and finance (49%).