Many workers have registered under the new scheme

Mr Blunkett is to address delegates at a key Trades Union Congress conference on migration in London on Wednesday.

He will also say enforcement raids have doubled over the last year, while the move of border controls to France have stopped many would-be illegal entrants.

He is also expected to reiterate his commitment to identity cards.

Tackling abuses

In May this year, 10 more countries joined the European Union and a registration scheme was set up to encourage people to come forward if they were working in the EU illegally.

New figures covering the period to the end of September are expected to show significant numbers of Eastern Europeans have now paid the �50 to register.

This has allowed the government to better monitor the labour market while tackling abuses.

Mr Blunkett will also say that legal migrant workers are needed to cover 600,000 job vacancies in the UK.

Pattern change

The government is also expected to face calls from the GMB union and the Transport and General Workers' Union for an armistice on unregulated workers in London, in an attempt to end exploitation.

Mr Blunkett will say legal migrant workers are needed to fill jobs

Mr Blunkett's speech comes a day after new research by the TUC indicated more of migrant workers were moving to the UK countryside.

Using Mr Blunkett's register to contact migrant workers, the TUC's findings showed the pattern of migration into the UK was changing.

Workers from the new Eastern European EU states more likely to be found in rural areas and small towns, compared with earlier waves of migrant workers who had tended to settle in large towns and cities

Hard-to-fill jobs

A TUC leaflet was sent to workers with their registration certificates, and, in the six months from May to October 2004, 1,600 Eastern European workers responded.

The research found many were in hard-to fill rural jobs and filling a previously unmet demand for low paid labour.

The greatest number - 60% - were from Poland, followed by Slovaks at 13% and Czechs at 9%.

The most popular counties for the new arrivals were Lincolnshire, Norfolk, Kent and Sussex.