Police have confirmed a man injured in a bushfire on the New South Wales South Coast has died in hospital.

The 84-year-old suffered burns on December 31 at Cobargo, after a blaze tore through the Bega Valley town.

The man was transferred to Concord Hospital in Sydney for treatment, where he died early Saturday morning.

His death brings the death toll from Cobargo's New Years Eve bushfire to three people, after father and son Robert Salway, 63, and Patrick Salway, 29, perished on the day of the blaze.

The pair had stayed behind to defend their property and farming equipment in Wandella, 10 kilometres west of Cobargo, but their bodies were discovered when family members returned to the property.

The NSW Rural Fire Service estimated dozens of buildings had been destroyed in the historic village, which has a population of 776.

Father and son Robert and Patrick Salway also died in the Cobargo blaze. ( Supplied )

The total bushfire death toll in New South Wales now stands at 21 people.