Major crime search concluded at Yatina | VIDEO

Officers from the SA Police Major Crime Investigation Branch have completed a search at Yatina in the state's mid-north as part of an ongoing investigation into the 1973 disappearance of Joanne Ratcliffe and Kirste Gordon.

Detective Inspector Greg Hutchins said the search involved an area being excavated and followed work done in the area in September.

"Police returned to an area at Yatina on Monday, 15 December 2014 utilising the services of a company with specialist equipment which was brought from Victoria to assist with the search of the well.  A forensic examination of a property was also completed with crime scene specialists," he said.

"Unfortunately we found no evidence relating to this ongoing inquiry into the disappearance of the girls. Their families have been informed of the situation."

The girls disappeared on August 25, 1973 when Joanne, aged 11, took Kirste, who was just four-years-old, to the toilet while they were attending an SANFL game at Adelaide Oval with their families.

They were last seen towards the end of the match near the southern gates of the oval, and witnesses reported they may have been seen later with an unknown man near Port Rd, Thebarton.

Video: SA Police

A million dollar reward is on offer by the SA Government for information leading to the conviction of the person responsible for their disappearance and likely murder.

The investigation identified that the girls may have been forcibly removed from the Oval by a man thought to be aged in his 40s.

Det Insp Hutchins said the previous occupant of the Yatina property - who died in 1999 - was one of a number of people linked to the incident, but police had been unable to substantiate his involvement.

"I stress that the current owners of the property being searched are in no way involved in the girls' disappearance.

"And at this time we can't rule the previous property owner in or out of the matter."

He said police did not expect to return to the property unless further significant evidence came to light.

"I would urge anyone with information to call Crime Stoppers on 1800 333 000 or report online at www.sa.crimestoppers.com.au."