(Corrects to Wednesday from Tuesday in paragraph 1. The story was earlier corrected to say "high" inflation data, not "subdued", in the same paragraph.)

Oct 27 (Reuters) - Australian shares erased early gains to edge lower on Wednesday, hit by losses in mining and gold stocks as commodity prices came under pressure and a sharp fall in supermarket major Woolworths Group, while high inflation data also weighed on sentiment.

The S&P/ASX 200 index was down nearly 0.3% at 7,425 after rising 0.2% and was set to snap a five-session rally. The benchmark closed flat on Tuesday.

Woolworths plunged 4.5% in its sharpest drop since February on flagging a slowdown in sales as lockdowns ease, making staples sub-index the top loser on ASX 200.

Aussie miners fell as much as 1% as copper prices dropped. Mining giants Rio Tinto and BHP Group were down about 1% and 0.8%, respectively.

Simultaneously, ASX-listed shares of diary producer a2 Milk tanked up to 11.5% in their worst session since Aug. 26, the biggest decliner on the benchmark after a grim trading update.

The gold sub-index slid as much as 1.4%, as bullion fell on dollar strength, with Kingsgate Consolidated leading losses, plunging 17.2%.

Sentiment was further hurt after data showed Australian core inflation jumped to a six-year high in the third quarter.

The financials' sub-index fell 0.2% after rising modestly, as investors awaited bank earnings starting on Thursday.

Three of Australia's largest banks, Australia and New Zealand Banking Group, Westpac Banking Corp and National Australia Bank, are expected to report a 79% jump in earnings.

Bucking the sombre mood, country's telecom stocks rose 1.7% to become the top gainer on the ASX 200, led by a 2.2% jump in Telstra Corp.

New Zealand's benchmark S&P/NZX 50 index was down 0.5% to 13,007.98, with a2 Milk, down 11.3%, dragging the index.

Also, an ANZ Bank survey showed that New Zealand business sentiment fell in October as cost and inflation pressures intensified due to COVID-19 uncertainty.

(Reporting by Savyata Mishra in Bengaluru; Editing by Rashmi Aich)