Masterton police constable Dana Johanson said she was the first officer to arrive on the scene and she gave Aspinall a roadside breath test, which showed he had a breath alcohol reading of more than 400mcg.
Due to that reading she told Aspinall that he had to accompany her to the police station for a breath test.
Senior constable Tony Matheson said while he was in the process of removing the keys from Aspinall's car ignition, he noticed a small, plastic pill container on the passenger seat.
"I saw it contained plant material that I thought was cannabis."
Mr Matheson said he then told Aspinall not to go into the car and to leave the pill bottle where it was.
Despite that, Aspinall took the pill bottle from the car, Mr Matheson said.
Aspinall's lawyer, Jock Blathwayt, said his client was not breath-tested on the side of the road, as he was not asked to by police.
He also denied the resisting charge, Mr Blathwayt said, because although Mr Matheson had told Aspinall not to go back to his car, Ms Johanson had said he could go to his car to get his reading glasses.
Mr Blathwayt conceded that, during cross-examination by Sergeant Jodie Lawrence, Aspinall admitted the cannabis was his.
Judge Michael Behrens said given that two witnesses testified Aspinall was breath-tested by the side of the road, he found him guilty of drink-driving. Aspinall was sentenced to 80 hours' community work, disqualified from driving for eight months and ordered to pay witness fees of $25.
On the cannabis charge he was convicted and discharged.
Aspinall was found not guilty of obstruction due to conflicting instructions given to him by police as to whether he could or could not retrieve something from his car.
