Hohepa Paetai "Joe" Bean, 43, pleaded not guilty to murdering Darren Boardman, 40, at a Dundurrabin property on October 18, 2018.

He pleaded guilty to manslaughter after shooting his former friend with a rifle but the Crown rejected this.

The jury was discharged on Monday in Coffs Harbour Supreme Court by Justice Richard Button who acknowledged that no more time would allow for a unanimous decision after "deliberating conscientiously for many hours".

The killing occurred following the breakdown of Bean's relationship with Toni Carter after 20 years spent together in Dorrigo.

She had recently moved to Queensland with Mr Boardman but the pair were back in the area for a medical appointment.

Bean says he was terrified for his life the day Mr Boardman hurtled down a driveway in a car which crashed into his ute.

His defence submitted Mr Boardman was trying to hit him with the speeding car so he ran inside and fetched his rifle for safety.

Ms Carter said she saw Bean aim the gun, pause, and then aim again and shoot into Mr Boardman's upper back as he was rummaging in the car for something.

Soon after she called emergency services but he died in the back of the ute.

Bail for Bean was not applied for while the matter has been relisted for mention on June 4.

Australian Associated Press