Accused Family Court bomber Leonard John Warwick has formally pleaded not guilty to a string of murders and bombings in Sydney in the 1980s.

Warwick is charged with multiple offences that include four murders, allegedly following a custody and property battle with his ex wife.

The 69-year-old is charged with the shooting murders of his wife's brother Stephen Blanchard and of Justice David Opas.

He is also accused of setting off one bomb that killed Pearl Watson — the wife of Justice Ray Watson — and another bomb that killed Graham Wykes in a Jehovah's Witness Hall.

Warwick has formally pleaded not guilty at his arraignment in the NSW Supreme Court.

Wearing prison greens, he appeared in court via video link.

He then pleaded not guilty to each of the long list of charges as they were read out.

The crimes allegedly committed by Warwick include:

the fatal shooting of his brother-in-law, Stephen Blanchard, in 1980

the fatal shooting of his brother-in-law, Stephen Blanchard, in 1980 the fatal shooting of judge David Opas in 1980

the fatal shooting of judge David Opas in 1980 the bombing of the home of judge Richard Gee in 1984

the bombing of the home of judge Richard Gee in 1984 the bombing of the Parramatta Family Court in 1984

the bombing of the Parramatta Family Court in 1984 the bombing of the home of Judge Ray Watson, killing his wife Pearl, in 1984

the bombing of the home of Judge Ray Watson, killing his wife Pearl, in 1984 the bombing of a Jehovah's Witness church hall, killing Graham Wykes and injuring other churchgoers, in 1985.

Prosecutor Gina O'Rourke said the crown case would revolve around seven incidents in the 1980s.

Leonard Warwick is charged with multiple offences including four murders. ( ABC News: Vincent de Gouw )

"The crown case is that they are all linked to Family Court proceedings," she said.

"The matters in relation to the Jehovah's Witnesses will be the strongest part of the Crown case."

The court heard DNA evidence and evidence about explosive material would be presented at the trial.

When asked about the defence case, Warwick's barrister Richard Thomas said: "There is simply a total denial of involvement at any level."

The trial is expected to run for six months and hear from more than 100 witnesses.

Justice Garling set a trial date of February 2018.

Warwick remains in custody.