Chinese security forces have arrested at least nine Christians who opposed the ruling Communist party's campaign to remove crosses from churches.

The Christians have been detained in the eastern province of Zhejiang. Tensions have been growing in the region since late 2013 when authorities began demolishing churches.

Christians have organised a series of protests in recent months against the campaign (ostensibly aimed at illegal buildings), with one Catholic leader denouncing the cross removals as an "evil act."

Authorities have been angered by the growing resistance with one church organising a month-long sit in.

A wave of arrests began on Tuesday to try and quell dissent.

"At least nine people I know have been taken away by the police and that figure is still rising," a local pastor said.

"We think it is a campaign targeting church leaders across the province. It can only be a co-ordinated action initiated by the provincial government."

More than 1,200 crosses have been removed from buildings in Zhejiang, activists say, and many churches have been completely demolished.

The ruling Chinese Communist Party (CPC) have gradually become more suspicious of the burgeoning Christian population as the demolition campaign has been accompanied by an increasingly negative government rhetoric regarding Christianity.

There were just one million believers when the CPC came to power in 1949 but there are now thought to be as many as 100 million. By 2030, one expert has estimated that China will be home to more Christians than any other country in the world.