A Tasmanian man charged with murdering his estranged wife had planned to instead kill himself in front of the Family Court to protest an 'unfair' legal system, a jury has been told.

Klaus Dieter Neubert, 74, allegedly shot and killed his wife Olga Neubert in May 2015, just nine days after she refused a $650,000 divorce settlement.

The 37-year-old was stopped at traffic lights in her Peugeot hatchback when Neubert allegedly blocked her path with his four-wheel drive and opened fire in front of onlookers.

Olga Neubert, 37, was allegedly shot and killed by her estranged husband Klaus Dieter Neubert, 74, in May 2015

At the start of a Supreme Court jury trial on Monday prosecutor Daryl Coates SC said the accused repeatedly fired a shortened .44-calibre rifle which he had been carrying around in his car for weeks.

'One of the shots, he placed the rifle directly onto Mrs Neubert's head and pulled the trigger, killing her almost instantly.'

A female passenger in the car was shot in the hand and subsequently lost two fingers.

Neubert has pleaded not guilty to charges of murder and causing grievous bodily harm.

The couple met in Mrs Neubert's native Philippines and were married in Australia in 1997 before moving to Tasmania, south of Hobart, in 2000.

During a 2014 trip to the United States to stay on board Neubert's yacht - part of his substantial property portfolio - Mrs Neubert started a relationship with another man, Mr Coates said.

She returned to Tasmania and launched divorce proceedings, refusing to make contact with Neubert, but lodging a family court application for a temporary $50,000 payment.

Olga was stopped at traffic lights in her Peugeot hatchback when Neubert allegedly blocked her path with his four-wheel drive and opened fire in front of scores of onlookers

In response, Neubert offered a $650,000 settlement, which he later described to police as 'kind and generous'. It was refused, Mr Coates said.

'The accused was angry and distressed with his wife who would not talk to him and who he could not find, and was frustrated with the court proceedings,' he said.

'The accused killed Mrs Neubert because she left him for another man. She would not talk to him, he felt humiliated ... and she would not settle the Family Court proceedings.'

On the day of the shooting, Neubert had seen his wife's car parked outside shops and followed her until traffic stopped at lights, police allege.

'He had the rifle in his car because he planned to shoot himself and was mindful to do it in front of the Family Court,' Mr Coates said, citing a police statement taken after the shooting in which Neubert expressed his belief the legal system was 'unfair'.

Witnesses wrestled the rifle from Neubert at the scene.

The trial is listed for three weeks before Justice Michael Brett.