Susan Goodwin was last seen grocery shopping in 2002. Police just found bones in a backyard.

Police have charged a man with murder, hours after bones were found during a search for the remains of a woman who vanished more than 20 years ago.

The breakthrough in the cold case was made late on Wednesday following the discovery of human remains, believed to be those of Susan Goodwin, 39, buried in the backyard of a house in Port Lincoln, South Australia.

Major Crime detectives arrested and charged a 64-year-old Port Lincoln man with the murder of Susan, who was reported missing in July 2002.

He will appear in Port Lincoln Magistrates Court on Thursday.

Watch: Murder charge laid after human remains discovered in cold case search. Post continues below.

"I'm very confident that we have found the remains of Susan Goodwin," Detective Inspector Andrew Macrae told a press conference on Wednesday.

Earlier, police said they had paused their search after the discovery of bones at a Port Lincoln property during preliminary excavations.

An anthropologist from Forensic Science SA examined the bones and confirmed they were human remains, police said.

Additional resources from the forensic response section and Major Crime branch have travelled to the area to continue investigations.

Police had been using specialised radar equipment to scan a property in Pamir Court, which adjoins Moonta Crescent, where Susan had lived.

On Tuesday, Macrae said it was "a tragedy that Susan's family have spent the last 23 years without answers''.

Susan was last seen about lunchtime on July 19, 2002, after shopping at Coles and Woolworths in Port Lincoln.

Police had previously said she was murdered "by someone who was very close to her" and they believe the killer still lives in the town.

In 2017, police said a public appeal for information had led to seven persons of interest being cleared by the investigation.

A reward of up to $200,000 is offered for information leading to the conviction of Susan's killer and/or information that leads to the recovery of her remains.

Feature image: SA Police.