The High Court trial against a man charged over the death of a woman picketer has opened in Christchurch.

Derek Powell is accused of motor manslaughter following the death of Christine Clark during a protest at Lyttelton on New Year's Eve 1999.

Television footage was shown to the jury on the first day of the trial.

The boat builder denied the charge and the court was told he will say he acted out of fear for his own safety.

But the Crown says while he was subjected to a picket line verbal altercation there was no physical attack.

The Crown alleges Powell lost his temper and put his foot down, driving through the picket line.

Witness Raymond Spain says Clark was struck by the car and carried a distance before falling and hitting the back of her head on the roadway. She was then run over.

The court heard it was the blow to the back of the head which proved fatal to the 45-year-old mother of two who died in hospital two days later.

Clark had been on the picket line to support watersiders who were angry over contracting out of coal handling at the Port of Lyttelton.

The Crown acknowledged the picketers should not have been blocking the road but said the police chose not to remove them.