Dramatic changes in employment over the last few years in the East has seen migrant labour become essential for many companies, a report claims.
The trend for migrant workers has grown
Born Abroad, which maps immigration in Britain using Census 2001 data, shows 328,131, or 6% of the eastern region's population, was born outside the UK.
Many companies say foreign recruitment is now essential to their survival.
Norfolk-based Bernard Matthews, where 30% of its workers are Portuguese, said it struggles to find local employees.
The East of England Development Agency estimates that the number of migrant workers arriving in the region within the last five years could be as high as 80,000.
'Could not cope'
Norfolk as a whole is home to an established Portuguese community with significant settlements in Dereham, Swaffham and Thetford in the Breckland area.
The Department of the Environment, Food and Rural Affairs (Defra) has calculated the Portuguese population to be in the region of 15,000.
In the Breckland area, the agricultural sector is focused on stock and poultry rearing and arable crops where much of the migrant worker population is employed.
A report commissioned by the Keystone Development Trust and funded by Breckland Council reveals a steady increase of overseas nationals arriving in the East of England.
Based on the interviews with employers, the report published in June this year found without migrant workers some firms would not be able to function properly.
Its findings show 17,400 migrant workers in the Breckland area in 2000/01 and 18,300 in 2001/02.
The rural east region is increasingly a key destination for many agricultural and food sector migrant workers, the report states.
The highest number are from Portugal but figures also reveal a steady influx from Poland, Lithuania, Latvia, Romania and the Ukraine.
William Nunn, leader of Breckland Council, told the BBC: "We need to see a change in attitude to migrant workers.
"They make a significant contribution to the rural economy and indeed without them, some businesses in our district would be unable to work at full capacity or might even need to look at relocating overseas to remain competitive."