The National Parks Board (NParks) officer who oversaw the purchase of 26 Brompton bicycles from supplier Bikehop was a personal friend of its director and had tipped him off about the government tender for the foldable bikes, it emerged in court on Tuesday.

Taking the stand on the first day of the trial against Bernard Lim Yong Soon for lying to auditors investigating the deal, Bikehop's then director Lawrence Lim Chun How said he had first met Bernard Lim in September 2011 at a night cycling event - some three months before NParks invited bids for the procurement of the bicycles.

Bernard Lim had tipped him off and Bikehop successfully put in a bid to supply the bicycles at $2,200 each at a total cost of $57,200.

Then before a March 2012 meeting with NParks to discuss a delay in delivering a batch of the bikes, Mr Lawrence Lim told a district court that the NParks officer Lim had told him to pretend they did not know each other.

When the deal came under public scrutiny following an article in Chinese daily Lianhe Zaobao on June 22, 2012, Bernard Lim called the Bikehop director up and told him to "unfriend" him on social networking site Facebook.

The two later met at a hawker centre in Shunfu Road, where Lim repeated his preference that their relationship be kept quiet.

Mr Lawrence Lim told the court he then told Bernard Lim it would be better to admit to their friendship. But Bernard Lim told him: "You don't understand civil service culture."

Acceding to the request, Mr Lim later told both NParks and MND that the two did not know each other. But he later came clean about the relationship, on the advice of a lawyer.

Lim has been suspended on half-pay since July 2012. Besides the charge of lying to public servants, he is also accused of getting Mr Lawrence Lim to do the same. If convicted of giving false information of public servants, he could be jailed for up to a year, fined up to $5,000, or both.