Restrictions on religion continue to increase around the world, a major new report warns today.

Nationalist parties or tendencies play an increasing role in harassment of minority faith groups, the study by the Washington-based Pew Research Center said.

The research analyses attitudes to religions in 198 countries using both a 'government restrictions index', focusing on political parties' policies and rhetoric, and a 'social hostilities index', focusing on individuals and organisations' language and actions.

It found the number of countries with 'very high' government restrictions on faith was the highest since the annual study began in 2007.

While most countries have low to moderate religious restrictions, the report, which measured changes in 2016, said: 'In many countries, restrictions on religion resulted from actions taken by government officials, social groups or individuals espousing nationalist positions.'

The report pointed to Donald Trump's rise in the US and Geert Wilders' Freedom Party calling for the 'de-Islamisation' of the Netherlands as examples.

The rise of nationalist rhetoric was particularly common in Europe, the study found, with about a third of European counties having nationalist parties that made political statements against religious minorities.

'Overall, Muslims were the most common target of harassment by nationalist political parties in 2016, typically in the form of derogatory statements or adverse policies,' lead researcher Katayoun Kishi said in the report.

'In the United States, Muslims were the targets of derogatory rhetoric and proposed discrimination,' the study added pointing to Trump's plans for a temporary ban on Muslim immigration and a proposed requirement that US Muslims register in a database.

While Muslims were targeted most frequently in Europe, around the world Christians were the most common victims of harassment, followed closely by Muslims.

'Christians were most likely to face harassment in the Asia-Pacific region, whether from government forces or social groups,' the report said.

'Muslims, on the other hand, were most likely to face harassment by both governments and social groups in Europe. Of the countries where Muslims were harassed by governments, 28 per cent were in Europe, while an even bigger share of the countries where Muslims were harassed by social groups (35 of 97, or 36 per cent) were in Europe.'