A megachurch pastor in Singapore is on trial for misusing church funds – but it may all be down to a misunderstanding, say supporters.

Kong Hee founded the 20,000-member City Harvest Church in 1989 with his wife Sun Ho, a musician.

He and five other church members were charged in 2012 with using church building funds to support his wife's musical career through a multi-million dollar investment bond scheme. They argue that the scheme was legitimate and that the money was returned to the church with interest. They face up to 20 years in prison if they are convicted.

Supporters point to cultural shifts in evangelicalism which they say are not well understood in the Singapore legal system. US pastor A R Bernard, founder of the 30,000-member Christian Cultural Centre in Brooklyn, told the Washington Times after a visit to Kong Hee's church that accepted practices in the US, such as churches and charities using their own films and "crossover artists" who perform religious and secular music for evangelism, are "strange" in Singapore.

"Change is taking place in the nation [of Singapore] that is part of a bigger picture," he said. "We don't pick and choose history. History happens when social, political, economic and even spiritual forces come together and effect change."

The prosecution's opening statement in May 2013 ridiculed the church leaders' contention that "pop music was a tool of evangelism that would help spread God's message".

Among Kong Hee's other supporters are Pentecostal pastor Mary Hudson, co-founder of the Keith and Mary Hudson Ministries in Santa Barbara, California, and mother of pop star Katy Perry, and evangelist Phil Pringle, senior pastor of C3 Church in Sydney, Australia.