Wakefield Wines has won both Best Australian Shiraz and Best Australian Shiraz under AU$25 at the 2015 Great Australian Shiraz Challenge.
Its award-winning wine, the 2014 Wakefield Estate Shiraz, has a UK RRP of £12.
The Wakefield Estate Shiraz was awarded a score of 19.5, one of the highest scores in the competition's history.
The Great Australian Shiraz Challenge was founded in 1994. It received 375 entries this year.
This is only the second time a single wine has won both trophies.
Mitchell Taylor, managing director at Wakefield Wines, said: "We are thrilled with the result. These award wins are a credit to the hard work and dedication of our vineyard and winemaking teams who craft top quality wines across our entire portfolio.
"We are humbled. It reaffirms our commitment to producing beautiful wines of great value."
Wakefield Wines is a family-owned business in the Clare Valley.
Founded in 1969, it was the first major Australian winery to bottle all its wines under screw-cap. It was also the world's first carbon-neutral wine range.
Wakefield recently appointed former Pernod Ricard wine development director Adrian Atkinson to the new position of European market manager.
Wakefield Wines is distributed in the UK by Louis Latour Agencies.
The Wakefield Estate Range is available at Majestic.