Car 'drifting' before Vic cyclist death

A woman fatally hit a cyclist before fleeing the scene and trying to hide her car, a Melbourne court has been told.

Stephanie Maher, 33, was allegedly seen drifting on the Nepean Highway before her car struck cyclist Julian Paul on November 26, 2013.

Mr Paul, 54, was heading home to Brighton East after working in the city, the Victorian County Court heard.

The engineer died about three weeks later after his life support was turned off, prosecutor Ray Gibson told the court.

Maher is on trial after pleading not guilty to culpable driving, failing to stop and failing to render assistance.

She spent the day of the incident cleaning her Moorabbin apartment before heading out for dinner with her three-year-old son about 7pm, the court was told.

Mr Gibson said witnesses spotted Maher driving erratically about two hours later.

He said one motorist noticed Maher had her eyes closed before her head dropped down as though she had nodded off.

Ms Maher's car was seen turning into a side street after it allegedly struck the back of Mr Paul without braking, he said.

Her vehicle was later found at a supermarket about 1km from her unit, the court heard.

Maher told police she didn't want to take the car home because she didn't want her unstable brother to see it, Mr Gibson told the court.

She also told police she thought a rock had flicked up and hit her car, and she was not aware she had struck a cyclist, the court heard.

Mr Gibson told the jury Maher was fatigued and should have known there was a risk of falling asleep, or losing control.

She'd had a number of "near-miss" accidents and should have been aware she wasn't fit to drive, he told the court.

Maher accepted she was driving when her car hit Mr Paul, her barrister, Leighton Gwynn said.

But she denied her driving was negligent, he told the court.

Maher also didn't deny leaving the scene.

"What is in dispute is whether she knew a person had been struck," Mr Gwynn said.

The trial continues.