Police have charged a man with the wilful murder of Sarah Spiers, a victim of the so-called Claremont serial killings in the 1990s.

Bradley Robert Edwards, 49, who had previously been charged with the murders of Ciara Glennon and Jane Rimmer, was on Thursday charged with Ms Spiers' murder.

The 18-year-old's body has never been found.

WA Police commissioner Chris Dawson said it was a "significant development" but he could not comment further.

Ms Spiers was one of three women to disappear in Claremont between January 1996 and March 1997 in a spate of crimes that came to be known as the Claremont serial killings.

Sarah Spiers disappeared in 1996. ( Supplied: Fairfax Media )

She went missing after a night out in Claremont on January 26, 1996.

The teenager had been out celebrating Australia Day and was last seen after leaving the Club Bayview nightclub in the early hours of the next morning.

She called a taxi to take her home, but when it arrived, she was nowhere to be seen.

"This development follows extensive inquiries by the Macro investigation team within the cold case homicide squad," Commissioner Dawson said.

Bradley Robert Edwards has now been charged with the murder of all three Claremont victims. ( Facebook: KLAC )

'Traumatic time' for Spiers family

He said Ms Spiers's family had been kept informed.

"This is a very traumatic time for the Spiers family, so I urge the media to please respect their privacy and do not attempt to contact them," he said.

"Sarah Spiers's family has expressly told the WA Police Force that they do not wish to make any comment about today's development."

He appealed for people to refrain from posting comments about the case on social media, warning those who did so could be liable for prosecution.

Sarah Spiers, Ciara Glennon and Jane Rimmer all disappeared from Claremont in the 1990s. ( ABC News )

Ms Rimmer vanished from the same Perth nightspot in June 1996 and her body was found in bushland near Wellard, south of Perth, two months later.

Ms Glennon disappeared from Claremont the following March and her body was found in scrub in Eglington, a northern suburb of Perth, a month later.

Police subsequently confirmed they were looking for a serial killer.

They made a breakthrough in the investigation in 2016 when Mr Edwards was arrested and charged with the abduction and murder of Ms Rimmer and Ms Glennon.

Last month police called for public help to identify a car linked to Ms Spiers' disappearance, and on Thursday Commissioner Dawson said they were still seeking information in relation to it.

Police want to track down a white 1992 Toyota Camry station wagon similar to the one pictured. ( Supplied: WA Police )

The car is a 1992 white Toyota Camry station wagon with the vehicle identification number (VIN) of 6T172SV2109318479.

The vehicle was deregistered a decade ago.

Edwards will appear in court next Wednesday charged over the three murders.