July 28 (Reuters) - Australian shares fell on Wednesday as the country's most populous city extended a lockdown to curb rising COVID-19 cases, while electricity poles-and-wires firm Spark Infrastructure jumped on a higher buyout offer.

The S&P/ASX 200 skidded 0.3% to 7,411.9 by 0056 GMT, with most sectors trading in negative territory. The index had closed at a record high on Tuesday.

Australian officials said they would extend a COVID-19 lockdown in Sydney as new cases remained high despite a month under strict stay-home orders, while Victoria and South Australia eased curbs from Wednesday.

Economists at Commonwealth Bank of Australia on Wednesday pushed back expectations for the country's next policy rate hike to May 2023 from late-2022, anticipating the need for extended support amid virus curbs.

Spark Infrastructure stood out with a 6% jump following a sweetened offer from a consortium including KKR that valued the electricity infrastructure investor at A$5.13 billion ($3.78 billion)

Among sub-indexes, tech stocks shed 0.7% as they tracked their Wall Street peers, which fell from record highs overnight.

Miners fell more than 0.5%, with heavyweights BHP , Rio Tinto and Fortescue Metals Group shedding between 0.9% and 1.1%.

Bucking the trend, the industrial subindex rose about 0.4%, helped by a 4% rise in ALS Ltd after the lab testing service provider bought a 49% stake in European pharmaceutical firm Nuvisan.

New Zealand's benchmark S&P/NZX 50 index gained 0.3% to 12,623.36. ($1 = 1.3570 Australian dollars) (Reporting by Tejaswi Marthi in Bengaluru; Editing by Subhranshu Sahu)