Australian shares fell on Monday, dragged down by tech stocks and as tensions surrounding Ukraine kept risk sentiment low globally, while AGL Energy soared after rejecting a $3.54 billion buyout offer.

The S&P/ASX 200 index was down 0.8% to 7,167 by 0030 GMT, extending losses after Friday's 1% drop.

Major indexes on Wall Street closed lower on Friday as escalating tensions in Ukraine and US warnings of a potential Russian invasion kept markets on edge.

Most sectors were in negative territory in Australia, with technology stocks tracking their US peers lower and leading losses on the domestic bourse.

Gold rally drives Australia shares higher

Tyro Payments fell as much as 19% and was the top loser on the sub-index, after posting weaker-than-expected results.

Software firm Altium slumped 10.6% to a five-month low after issuing a downbeat margin guidance.

Meanwhile, AGL Energy rose 13% to its highest since July 19 after the power producer rejected a A$4.94 billion buyout offer from tech billionaire Mike Cannon-Brookes and Canada's Brookfield Asset Management.

Heavyweight financials fell 0.8%, with the so-called "Big Four" banks and buy now, pay later company Zip Co Ltd leading the decline.

Fuel suppliers Ampol Ltd and Viva Energy fell 1.7% and 4.4%, respectively, even after posting full-year profits compared to year-ago losses.

Oil prices gained more than $1 in early trade on jitters over potential conflict between Russia and Ukraine, with the United States and European Union making clear Russia would face sanctions if it invaded its neighbour.

Among gainers, gold stocks rose 1.2% on stronger bullion prices.

New Zealand's benchmark S&P/NZX 50 index slipped 0.5% to 12,080.94.

Shares of a2 Milk rose 10.3% to their highest since Nov. 29, after the dairy producer said it expected second-half revenue to be significantly higher than a year earlier.