Murdered farmer Scott Guy had "pissed a lot of people off", and his death had a bright side for one disgruntled farm worker, a court has heard.

Ewen Macdonald, 32, went on trial in the Wellington High Court on Tuesday, charged with shooting dead Mr Guy - his brother-in-law - on the driveway of his Aorangi Road property, on the outskirts of Feilding, in the early hours of July 8, 2010.

Simon Asplin, who works as an assistant manager on the Guy family's farm, told the court he had arrived early at the farm that day, and was surprised to see another farm worker, Matthew Ireland, was already there.

When Macdonald arrived a short time later, they joked about how Mr Guy - who they dubbed "Sleeping Beauty" - was once again late for work.

Later that morning, Macdonald called Mr Asplin to tell him Mr Guy had been in an accident, before another friend phoned Mr Asplin to say they had heard Mr Guy had been shot, the court heard.

A few days later, while at a fertiliser depot, Mr Asplin commented to a staff member that "one good thing that's come out of this is that I'm back on the tractor where I belong" - referring to a role that Mr Guy had largely taken out of his hands when he returned to the farm after a hiatus.

When the worker asked who could have killed Mr Guy, Mr Asplin responded by saying Mr Guy had "pissed a lot of people off".

The alarmed shopkeeper contacted police, who then interviewed Mr Asplin.

Under cross-examination by defence counsel Greg King, Mr Asplin said he had had a difficult relationship with Mr Guy.

"I [didn't] get along with him a lot of the time but I didn't hate him," Mr Asplin said.

He admitted he had been "upset" about not operating the tractor as much as he used to, and that Mr Guy pissed him off at times.

Earlier, the jury of seven men and five women was told how Macdonald admitted to police in April 2011 that there had been tensions between him and Mr Guy, including over who would inherit the Guy family farm.

He admitted charges of arson and criminal damage over a fire and vandalism of houses on Mr Guy's property.

Macdonald's lawyer Greg King told the court those were "very foolish, very nasty acts" but did not make Macdonald a murderer.

Truck driver David Berry, who discovered Mr Guy's body while driving past his property, took the witness stand late on Tuesday and will continue his testimony on Wednesday.