Ben Carson is the most favoured republican presidential candidate for white evangelicals, a survey has found, while Donald Trump is the least favoured.

The Washington-based Public Religion Research Institute released its American Values study this week, including a supplement survey of opinions of presidential candidates.

Out of Republican voters, Carson had the most support with 27 per cent and Trump came second with 20 per cent.

However when it came to favourable opinions of the candidates, 55 per cent of white evangelicals said they had a favourable view of Carson, while only 26 per cent they held an unfavourable view of the retired neurosurgeon. In contrast, only 39 per cent said they held a favourable view of Trump and 52 per cent had unfavourable opinions of him.

This represents a significant disparity between the national political polling, which has Trump leading the chase for the republican presidential nomination with 24.8 per cent of the vote.

Opinions of Texas senator Ted Cruz were split according to the survey, with 31 per cent viewing him favourably and 32 per cent unfavourably.

The American Values Survey also found that white evangelicals tend to have a more pessimistic view about the state of the US and the direction it is taking. Six out of ten believe that "America's best days are behind us" whereas 56 per cent of Catholic and 57 per cent of black protestants believe that America's best days are yet to come.

"Both white Evangelical Protestants and the white working class, have seen a massive decline in their public influence and respect of their views in the public square," said Henry Olsen a senior fellow at the Ethics and Public Policy Centre at the survey's release.

"It is no wonder than that they think the best days are behind us, because for them, they are."