Approximately one third of the Adelaide Hills' wine production capacity has been wiped out by devastating bushfires in South Australia. (Photo: Xinhua)

CANBERRA, Dec. 25 (Xinhua) -- Up to one third of the Adelaide Hills' wine production capacity has been wiped out by devastating bushfires in South Australia (SA).

The Adelaide Hills, one of SA's most farmed areas, was hit hardest by fires that burned through much of the state over the weekend.

More than 20,000 hectares of farmland were lost to fires in the region, including the grapevines of the Adelaide Hills' renowned wineries.

"What we do know is approximately 1,100 hectares of grapevines are burnt," Jared Stringer, the vice-chair of the Adelaide Hills Wine Region, told the Australian Broadcasting Corporation (ABC) on Tuesday.

"That makes up approximately one-third of Adelaide Hills production, so for any industry to lose one-third overnight it's going to be incredibly devastating."

Steven Marshall, the premier of SA, revealed on Sunday night that more than 70 homes were destroyed in the hills, up from the previous estimate of 15.

The Guardian Australia on Tuesday published a memo sent to the government in May, in which the Department of Home Affairs warned of greater bushfire risk.

The government and Prime Minister Scott Morrison have faced significant criticism for failing to prepare for the bushfire crisis which has affected much of the country in November and December.

"The physical effects of climate change, population growth, and urbanization mean that without effective action more Australians' livelihoods will be impacted by disasters into the future and the cost of those disasters will continue to grow," the memo said.

"Coordinated national action to drive efforts to reduce these risks and improve national resilience is required."