A recent survey released by Pew research centers found substantial gaps within the two parties -- and between them -- over key elements of immigration policy and the impact of immigrants on the United States.

About 59 per cent of the population continues to favour a proposal to allow undocumented immigrants who have been in the United States for several years to gain legal working status and the possibility of future citizenship. Most moderate and liberal Republicans (60 per cent) favour the path to citizenship, but just 45 per cent of conservative Republicans agree.

Democrats also differ over a proposed path to citizenship for illegal immigrants, though solid majorities of both liberal Democrats (76 per cent) and conservative and moderate Democrats (62 per cent) favour this approach.

Bush said, the Government's stepped up enforcement measures including a new fence along the Mexican border have cut down on the number of illegal immigrants entering the country.

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