Supporters of a man on trial for growing and selling cannabis are picketing the Palmerston North courthouse and handing out pro-cannabis leaflets.

Inside the building, William Duffield McKee, known as Billy, is facing four charges of selling the drug and one of cultivation, having been caught in an undercover police sting.

The 57-year-old Levin man hosts the GreenCross website, which promotes the use of cannabis for medical purposes.

McKee's supporters were standing near the door when potential jury members reported for duty yesterday.

Once the Palmerston North District Court jury was chosen, Judge Barbara Morris told them to destroy any pamphlets they might have been handed.

She also told them to put aside any views they might hold about cannabis use.

“You must not convict McKee because you hold a political view on this topic. You must not acquit McKee because you hold a political view on this topic,” the judge said.

In her opening statement, Crown prosecutor Andrea Read said police were concerned drugs were being sold over the GreenCross site and began an undercover operation.

A police constable, who used an assumed name that is suppressed, rang a GreenCross phone number in February, 2010.

“He explained that he suffered from migraines and the accused offered medical advice and recommended hemp oil,” Ms Read said.

The constable put $25 in the GreenCross bank account and received the oil on March 9, 2010.

McKee is accused of emailing the constable to ask if he would like to buy any cannabis, or “raw medicine”.

The constable emailed back and said "yes", but McKee said he would first have to join GreenCross, which he did.

On June 23, 2010, it's alleged the pair met at a “secluded park” in Petone where McKee sold the constable oil and two matchboxes of cannabis plant material for $65.

Another meeting was arranged for July 7, 2010, where McKee is accused of selling two matchboxes of cannabis plant material for $40 in a Wellington car park.

http://www.stuff.co.nz/manawatu-standard/7609278/Accuseds-supporters-picket-court

The constable also asked if he could buy a $100 bag and allegedly gave McKee cash and an address to send the drug on to. It arrived on July 9, 2010, Ms Read said.

And on May 25 last year, the constable and McKee met in a Levin car park where McKee is accused of selling him cannabis and oil for $125.

McKee's house was searched on July 8, 2011, and police found a trapdoor hidden under the carpet, Ms Read said. “Under the trapdoor police located a cannabis grow room containing 66 cannabis plants in various stages of growth.”

McKee is representing himself, but lawyer Steve Winter has been appointed by the court to assist him.

Mr Winter reminded the jury to keep an open mind and said the Crown had to prove the charges.

“From McKee's perspective, almost [as] important as what happened is why it happened.”

The public gallery was cleared when the undercover constable gave evidence.

He said at one of his meetings with McKee, the accused told him he could not be prosecuted if he had his GreenCross membership card on him while carrying cannabis. The trial is expected to last three days.