A glassware firm and its owner accused of helping six City Harvest Church leaders to misuse church funds denied knowledge of a "secret" plan by several of them.

The State produced e-mails on Wednesday to try and show that some of the accused had cooked up a ploy to get around the terms of an investment contract between the church and the company, Firna.

The church wanted to invest $11 million into Firna bonds. This was a way of illegally diverting church funds to finance City Harvest co-founder Ho Yeow Sun's music career, the State believes. In the investment contract, City Harvest had built in a clause to protect itself - it could convert the bonds into shares in the company if the money was not returned when the bonds matured.

Later, however, several of the accused wrote in emails of a "secret letter" to be sent to Firna's owners, in which the church would promise to sell back the shares "at a nominal value of US$1" if the conversion happened, effectively voiding the protection.

This ploy was needed to get the firm on board with the plan to funnel church funds, the state believes. When asked about this, Firna owner Wahju Hanafi said that he and his father-in-law, co-owners of the firm at the time, did not know of this plan and was not involved in it.

Mr Hanafi also maintained that Firna's money had not been used to finance Ms Ho's career, and that it was his own money that was used.

City Harvest founder Kong Hee and five of his deputies were charged last year with misusing about $50 million of church funds.