* ASX cites investigation on 'market data issues'

* Buy-now-pay-later stocks subdued after regulator's report

* NZ index on track for a 10-session winning streak

Nov 16 (Reuters) - Trading on the Australian Securities Exchange was halted on Monday as the stock exchange operator cited "market data issues", shortly after shares touched their highest in more than eight months.

The S&P/ASX 200 index gained 1.3% at 6,487.30, its highest since March 8. The index was riding high on vaccine optimism that offset worries about fresh lockdowns globally and helped most Asian markets start the week on firm ground.

"The ASX equity market is currently paused and there is no trading while we investigate market data issues," ASX said https://bit.ly/35yCzXH on Twitter without giving more details, but said it was working to rectify the issue as soon as possible.

Prior to the trading halt, financial stocks fuelled index gains, with the country's so-called "Big Four" banks trading up as much as 3%.

Fund managers Pendal Group and Challenger Ltd each added around 3%.

Brent crude futures rose 0.4%, boosting energy stocks. Papua New Guinea-focused Oil Search Ltd rose 3%, while sector heavyweight Woodside Petroleum added 1.2%.

A 0.2% rise in Chinese iron ore futures helped the index's heavyweight miners, with BHP Group Ltd adding 2.1% and rival Rio Tinto Ltd climbing 1.8%.

A spike in South Australia's new coronavirus cases, however, caused a neighbouring state to reimpose border controls and the federal government to offer help.

Buy-now-pay-later stocks were subdued after the country's financial regulator published a long-anticipated report on the sector that showed one in five consumers were missing payments and some were facing financial hardship.

Sector leader Afterpay Ltd eased 1.6% while Zip Co Ltd lost 1.3%.

New Zealand's benchmark S&P/NZX 50 index rose 1.2% to hit a record high at 12,854.50, on track for its 10 consecutive session of gains.

Air New Zealand was among top gainers with a 3.5% rise, while Ryman Healthcare added 2.5%.

(Reporting by Rashmi Ashok in Bengaluru, Editing by Sherry Jacob-Phillips)