The team comprised four plant scientists from the Office of Environment and Heritage, The National Parks and Wildlife Service, the Australian National Botanic Gardens and the Australian National Herbarium.

The two-day field trip followed in the steps of prominent botanists, Baron von Mueller, who explored the discovered several Australian species from 1852 onward.

After seven hours of difficult trekking through rocky gorges and dense undergrowth, the team returned with samples of Genoa River Correa, which was first discovered by Mueller in 1860, as well as the rare species Deane's Boronia, Pomaderris Cotoneaster and Nalbaugh Nematolepis.

OEH Senior Threatened Species Officer,Dr Keith McDougall, said the Genoa River Correa had not been seen since 1999 and the Nalbaugh Nematolepis was last seen in the 1980s.

"We were lucky to find the Correa because there was not very much of it there," he said.

Fog made accessing the remote area by helicopter impossible and Dr McDougall said despite considering turning back, these finds made him glad they stuck it out.

"We stayed overnight at the same cattle station in Nungatta where Mueller visited more than 150 years ago and looked out over the same landscape," Dr McDougall said.

Australian National Botanic Gardens' Joe McAuliffe said prior to the exhibition neither live cuttings nor seed had been collected for the four rare species.

"Cuttings were taken from the plants and will be grown at the Australian National Botanic Gardens in Canberra, establishing a living collection and essentially insurance against extinction," Mr McAuliffe said.

The ACT and NSW teams cooperative expedition delivered great results and was made possible through the $100 million NSW Saving our Species program.

A return expedition is planned in spring this year to establish monitoring programs for the long-term protection of all four species.