Australia’s share market has fallen by almost one per cent and is headed for its fourth consecutive weekly loss after US markets closed lower on more selling of big-name technology stocks.

The S&P/ASX200 benchmark index was lower by 55.1 points, or 0.93 per cent, to 5853.4 points at 1200 AEST on Friday.

The All Ordinaries index was down by 58.5 points, or 0.96 per cent, to 6031.5.

The materials sector was lower by 1.34 per cent and financials were down 1.26 per cent.

The information technology sector had the greatest fall on the ASX, 1.94 per cent, after Apple, Microsoft and Amazon fell heavily on US markets.

Health was the only positive sector on the local bourse, up by 0.04 per cent.

Rio Tinto shares were down 0.26 per cent to $100.18 after the global mining giant said the CEO and two executives had resigned after an investor revolt over the destruction of the Juukan Gorge in Western Australia.

Jean-Sebastien Jacques will stay as chief executive until a successor is found or until March, whichever comes first.

Iron ore boss Chris Salisbury and corporate relations manager Simon Niven will also leave.

The resignations come after pressure over the destruction of Aboriginal sacred sites dating back 46,000 years.

Rio shares fared better than fellow resources giants BHP, which lost 1.35 per cent to $36.48, and Fortescue, which slumped by 3.38 per cent to $17.28.

Meanwhile, Westpac’s boss believes the $900 million it has set aside for an eventual settlement with financial regulator AUSTRAC over breached anti-money laundering laws is adequate.

Peter King told federal MPs the bank has admitted to a substantial majority of breaches and it continues to work with AUSTRAC.

“It remains our preference to settle the matter,” Mr King told the House of Representatives economic committee.

“Ultimately it is the court that decides on the penalty.”

Westpac shares were down by 1.23 per cent to $16.79. Among its main rivals, ANZ fell 1.29 per cent to $17.48, Commonwealth Bank dropped 1.28 per cent to $65.86 and NAB shed 1.03 per cent to $17.14.

In IT shares, Afterpay was down 2.57 per cent to $73.68.

In the US overnight, tech stocks accounted for the biggest share of the broad sell-off on the S&P 500.

The sector has been at the centre of the market’s swings, hurt by criticism that their recession-defying surge in recent months was overdone.

The S&P 500 fell 59.77 points, or 1.8 per cent, to 3,339.19, its fourth decline in five days. The Dow Jones Industrial Average dropped 405.89 points, or 1.5 per cent, to 27,534.58. The Nasdaq gave up 221.97 points, or about two per cent, to 10,919.59.

The Aussie dollar was buying 72.68 US cents at 1200 AEST, lower from 72.82 US cents at the close on Thursday.