Islam is growing faster than any other religion in the world, according to a new study.

Muslims now make up 25.6 per cent of the global population, while Christians make up 28.8 per cent, the report - which was released by the Pew Research Center on Monday - says.

But the growth of Christianity has not kept up with the global population increase, with the religion's worldwide share slipping by 1.8 per cent.

This fall-off is largely driven by disaffiliation, as well as aging populations and lower fertility rates.

The Muslim population's share, on the other hand, increased by 1.8 per cent.