* Travel stocks fall on lockdown, reports of more COVID-19 cases

* Mining sector marks worst session in nearly three weeks

* Energy stocks slip on lower oil prices

March 30 (Reuters) - Australian shares fell on Tuesday, with mining and energy stocks weighing the most, while investors were cautious about placing big bets as more COVID-19 cases were reported in Queensland after the state capital Brisbane was put under lockdown.

The S&P/ASX 200 index ended 0.9% lower at 6.738.40, extending losses from the previous session.

Queensland warned on Tuesday that more cases of COVID-19 were expected to emerge as authorities scrambled to contain an outbreak linked to the virulent UK variant, throwing Easter travel plans into disarray.

"(Brisbane) had locally acquired cases which, compared with countries around the world, isn't much at all but it's generally been enough to see markets remaining a touch jittery," said Steven Daghlian, market analyst at CommSec.

"If case numbers continue to lift in coming days, there is a chance that the three-day lockdown is extended into Easter."

Most travel-related stocks fell on the news, with Webjet and Flight Centre weakening about 2% each.

Mining stocks closed more than 2% lower after marking their worst session in nearly three weeks, as iron ore futures dipped.

Global miners BHP Group and Rio Tinto each declined over 2%.

Gold stocks fell 2.2% to mark their lowest close since March 17, as bullion prices slipped to their weakest in more than two weeks.

Resolute Mining fell 7.7% while Red 5 shed nearly 3%.

The energy sub-index closed the session 1.6% lower, with all its components ending in the negative territory, hurt by a fall in oil prices.

Santos fell 1.1% while Woodside Petroleum lost 1.4%.

New Zealand's benchmark S&P/NZX 50 index gained 0.6%to finish the session at 12,446.76.

Top gainers were Auckland International Airport and Spark New Zealand, each advancing about 4%.

(Reporting by Nikhil Subba in Bengaluru, Editing by Sherry Jacob-Phillips)