Dec 20 (Reuters) - Australian shares dropped on Monday, dragged down by losses in financial and energy stocks as worries surrounding the Omicron coronavirus variant kept global markets on edge, while Magellan Financial Group dived after losing a major investment mandate.

The S&P/ASX 200 index was down 0.4% at 7,276.5 by 2352 GMT, heading for a fourth session of losses in five.

New coronavirus infections in Australia remained elevated over the weekend, with outbreaks growing in the country's two most populous states of New South Wales and Victoria.

Officials, however, said there was no need to clamp down on Christmas festivities even as new COVID-19 infections climbed in Sydney, with the country's high vaccination rate helping keep people out of hospital.

Energy stocks tracked oil prices lower, as surging cases of the Omicron variant raised fears that new restrictions may hit fuel demand.

Major oil and gas explorer Santos dropped as much as 2.7% to its lowest since Dec. 2, while Woodside Petroleum fell 1.9%.

Financials dropped more than 1%, with the so-called "Big Four" shedding between 0.5% and 0.9%.

Magellan Financial sank as much as 30% and was on track for its worst session ever, as the fund manager lost an investment mandate from UK-based St James' Place, which currently accounts for about 12% of its annual revenue.

Miners were down 0.7%, with BHP Group and Newcrest Mining dropping 1.3% and 1%, respectively.

Meanwhile, Rio Tinto named Canada's outgoing ambassador to China as its chairman, hoping the veteran consultant's links to its biggest market will help the global miner as it looks to move on from the scandal over its destruction of ancient rock shelters in Australia.

Shares of the global miner, however, were down 0.7%.

Limiting the benchmark index's losses, technology and healthcare stocks gained 0.8% and 1.4%, respectively.

New Zealand's benchmark S&P/NZX 50 index was largely unchanged at 12722.51. (Reporting by Harish Sridharan in Bengaluru; Editing by Subhranshu Sahu)