Immigration has been a problem area for the government

Under the plans, the Immigration and Nationality Directorate (IND) would become a semi-independent agency.

The move comes after months of high-profile problems with the management of asylum seekers.

Maeve Sherlock of the Refugee Council said she hoped the change would lead to a "fairer and more effective" system.

"If the planned changes improve the efficiency of the Home Office, that can only be a good thing. Crucially, we hope that the planned changes lead to an improvement in the decision-making process," Ms Sherlock said.

Keith Best of the Immigration Advisory Service said his organisation had been calling for the IND to be set up as an executive agency since the 2001 general election.

"We have advocated an independent board staffed by people who are interested in their work as a career and not just a temporary posting," Mr Best said.

'Irregular population'

The overhaul of the IND comes two months after Home Secretary John Reid admitted his department was "not fit for purpose".

Immigration remains one of the Home Office's biggest problems, with the backlog of failed asylum-seekers now revealed to be even bigger than the 283,000 cases estimated last year.

In spite of a new agency we will still have an asylum system which makes it extremely difficult for people to get human rights protection Rhian Beynon, Joint Council for the Welfare of Immigrants

A trawl of files in the Immigration and Nationality department has produced between 400,000 and 450,000 cases.

A spokeswoman for the Joint Council for the Welfare of Immigrants (JCWI) said that while the restructuring of the IND might prove beneficial to immigration applicants in the long-term, it would not address how to deal with current failed asylum seekers.

"By our reckoning any new agency would need to multiply the annual deportation rate by five, to 100,000 migrants a year, and spend around a billion pounds a year on deporting them to make any dent in the "irregular" population," Rhian Beynon said.

"In spite of a new agency, we will still have an asylum system which makes it extremely difficult for people to get human rights protection and creates a large group of failed asylum seekers, many of whom the government acknowledges are unable to leave the UK," she added.