Australia's largest private landholders have added to their portfolio. 

The Oldfield/Costello families have purchased the NT's Mount Doreen Station, covering more than 730,000 hectares, 400 kilometres north-west of Alice Springs.

The purchase means Viv Oldfield, alongside Don and Colleen Costello, now own more than 9.2 million hectares across the Northern Territory, Western Australia's Kimberley region and South Australia's far north.

They became Australia's largest private landholder after purchasing Innamincka and Macumba stations from Gina Rinehart earlier this year.

NT Land Titles Office documents show Mount Doreen sold for $34.7 million. Reports say the property came with about 18,000 head of cattle.

Mount Doreen had been held by the Braitling family since it was established in 1932. The property has an average rainfall of about 300mm. 

It is the latest acquisition in something of a buying spree by the Oldfield/Costello families, who operate as Crown Point Pastoral.

As well as the SA properties purchased from Ms Rinehart, the group also bought WA's Ruby Plains and Sturt Creek in late 2021.

Mr Oldfield was part of a group of Australian pastoralists who bid for the S Kidman and Co. property portfolio in 2016, but ultimately lost out to Ms Rinehart.