Australian shares dipped for a second straight session on Tuesday, weighed down by losses in Westpac Banking Corp after the lender flagged a $956.54 million hit to its second-half profit from one-off charges.

Shares of the country's second-largest bank fell 1.7%, while the benchmark ASX 200 index slipped 0.3% to 7,280.7.

Casino firms Star Entertainment Group and Crown Resorts extended their losses on fears of tighter regulatory scrutiny.

Star slumped 23% on Monday after media outlets detailed a confidential review that showed the company failed to do enough to prevent money laundering and fraud at two casinos.

"Investors appear to be concerned about drawn-out regulatory scrutiny in the casino industry, which is being frequently criticised for encouraging money laundering and fraud activities," said Kunal Sawhney, chief executive officer of equities research firm Kalkine Group.

Energy, hurt by lower oil prices, and tech stocks also gave up more than 1% on Tuesday.

Buy now, pay later firm Zip Co Ltd ended the day more than 3% lower after Citi downgraded the stock on lower customer growth following the rebranding of its US unit.

Helping keep broader losses in check was a near 2% gain by biotech CSL Ltd, one of Australia's largest companies by market value, after the blood plasma and vaccine maker stuck to its profit guidance even as it battles higher costs.

Shares in neighbouring New Zealand fell 0.2%, sealing a sixth session of losses - its longest run since May.

Air New Zealand and Auckland Airport, extended their declines as the reopening of travel remains slow.