The inquest into the 1975 gangland-style murder of Perth brothel madam Shirley Finn will take longer than expected after explosive evidence at an earlier hearing prompted more witnesses to come forward.
The inquest officially opened on Monday but with Coroner Barry King's principal counsel suddenly unavailable, limited evidence will be heard from witnesses for the first fortnight.
"This is an unfortunate set of circumstances and I can assure everyone that there is nothing nefarious or sinister about it," Mr King said.
Ms Finn's daughter Bridget Shewring, who has long campaigned for the inquest and was present in court, is due to give evidence on Wednesday.
Last month, former policeman James Boland testified at a hearing that was scheduled at the last minute, and was questioned about information provided to him by a member of the public soon after Ms Finn's death - that Sydney underworld figure Arthur "Neddy" Smith had killed her.
Mr King said other witnesses came forward after Mr Boland's evidence and set down November 20 to 30 and December 11 to 22 as further sitting dates, saying he expected the inquest would continue into 2018.
Ms Shewring was accompanied by author Juliet Wills, who wrote the book Dirty Girl, and declined to speak to media when she left the court.
Her 33-year-old mother was wearing a ball gown and sitting in her parked car at a South Perth golf club, next the freeway, when she was shot four times to the head at close range in June 1975.
She was being investigated by the tax office over a $100,000 bill and had threatened to name people she had been involved with, or paid kickbacks to.
Cover-up rumours have surrounded the case, with an investigator at the time of the murder linked to corrupt NSW detective and convicted killer Roger Rogerson.
Former Liberal WA premier Ray O'Connor, who was jailed for six months in 1995 as part of the WA Inc scandal and died in 2013 aged 86, has also been linked to the case.
Ms Finn's driver Leigh Beswick told Australian Story they were close, but Mr O'Connor denied ever meeting her.
Ms Beswick said her employer threatened to take him "down" with her three days before her murder, when he was the police minister.
A new investigation into Ms Finn's death was launched in 2014 following a cold case review but didn't result in any charges being laid.