* Tech index down 2.2%, fall for 4th straight session
* Afterpay shares fall over 20% since Wednesday
* Mining stocks snap four sessions of declines (Updates to close)
Oct 21 (Reuters) - Australian shares were shackled on Monday by Brexit uncertainty, with declines in the tech and energy sectors largely offsetting gains in mining stocks.
The S&P/ASX 200 index .AXJO closed flat at 6,652.50, having given up 0.5% on Friday.
British Prime Minister Boris Johnson's plan to put his Brexit withdrawal deal to the UK parliament on Saturday was derailed after lawmakers voted to withhold a decision on the agreement, forcing him to seek a third postponement of Britain's departure from the bloc. Daghlian, market analyst at CommSec, said the uncertainty surrounding Brexit is just adding another layer of concern in a slowing global economy.
On the day, the technology sub-index .AXIJ retreated 2.2% as digital payments stocks slipped further after the central bank on Thursday said https:// it planned to review some practices in the buy-now-pay-later sector (BNPL).
Shares of BNPL bellwether Afterpay Touch Group Ltd APT.AX slipped as much as 3.3% to a near two-month closing low, although the company said on Monday it was not currently part of the central bank's review. stock has fallen more than 20% in the past four sessions since brokerage UBS started coverage with a 'sell' rating as it sees the sector at risk of further regulation. stocks .AXEJ fell for a second straight session as oil prices eased on Monday amid persistent concerns about the global economic outlook and the impact on oil demand. O/R
Woodside Petroleum Ltd WPL.AX lost 0.8%, while Beach Energy BPT.AX declined 1.7%.
Offering some relief, the mining sector .AXMM advanced 0.5% as investors bought into stocks that tumbled last week over concerns about Chinese demand.
Rare earths miner Lynas Corp LYC.AX saw its best session in more than six weeks on an upbeat quarterly report.
The company posted a jump in sales revenue against the preceding quarter, and noted increased interest from magnet makers in the United States and Europe for long-term contracts of its products. the Tasman, New Zealand's benchmark S&P/NZX 50 index .NZ50 slipped 0.04% to 11,062.75.
Tourism Holdings THL.NZ tumbled 10.6% and ended at a near two-month low, after it said it would not provide specific guidance for fiscal 2020 due to volatility in the U.S. market.