* Gold miners led gains on ASX

* Buy-now, pay-later firms capped gains

* NZX 50 down 0.5%

July 14 (Reuters) - Australian shares closed higher on Wednesday, outweighing any investor concerns after a lockdown was extended in the country's most populous city, with heavyweight gold miners helping offset turmoil in the buy-now, pay-later sector.

The S&P/ASX 200 index rose 0.31% to 7,354.7 points, with all sectors except buy-now, pay-later in the black.

Lockdown in Sydney was extended by two weeks after a rise in new COVID-19 cases with total infections across the harbour city nearing 900.

"The market was not very fazed after the announcement of lockdown extension in Sydney but if the lockdowns persist any further than that, whatever economic recovery the country has made will be reversed," Steven Daghlian, market analyst at CommSec said.

"The only silver lining is investors are a little less pressured now and their risk appetites are improving as they know the pattern of how things roll under a lockdown."

Australia's gold miners closed 2.8% higher, touching their highest since June 17, as the precious metal firmed overnight after data showed U.S. consumer prices rose by the most in 13 years last month.

The country's biggest listed gold miner Newcrest Mining added up to 2.9%, ending higher for the third day, and gold miners Evolution Mining and Ramelius Resources were among the top gainers on the benchmark, advancing up to 4.8% and 5.1%, respectively.

In contrast, Australia's buy-now-pay-later firms tumbled about 10% on a report that Apple Inc is working on a service that will let users pay for purchases in instalments.

Buy-now-pay-later juggernaut Afterpay plunged as much as 9.7%, while Z1p Co skidded up to 11.4% as Apple's entry in the lucrative space could fuel solid competition in the sector.

"With the launch of Apple's BNPL product, sector darling Afterpay might no longer remain the only bigwig in the industry," Daghlian said.

Australian mining stocks closed 0.6% higher on the back of strong iron ore prices, with miner SSR Mining Inc advancing the most, up 4.95%.

Across the Tasman Sea, New Zealand's benchmark S&P/NZX 50 index fell 0.5% to 12,719.68 after the central bank left cash rate unchanged. (Reporting by Riya Sharma in Bengaluru; Editing by Shailesh Kuber)