The Australian share market has tumbled as investors appeared spooked by renewed concerns about the trade conflict between China and the United States.

The benchmark S&P/ASX200 index was down 67.5 points, or 1.07 per cent, to 6,268.3 points at 1200 AEST on Monday, while the broader All Ordinaries was down 71.1 points, or 1.11 per cent, to 6,356.1.

The ASX200 volatility index, a measure of local investor sentiment sometimes called the “fear index”, spiked more than 26 per cent on Monday to its highest point since early January.

The Wall Street Journal on Monday cited a source saying China was considering cancelling trade talks with the US after President Donald Trump tweeted overnight that he would hike tariffs on $US200 billion worth of Chinese goods this week.

All sectors of the ASX were in negative territory by midday.

Tech shares were leading losses – collectively down 2.06 per cent – followed by the energy sector, down 1.82 per cent, and consumer discretionaries that slid 1.75 per cent.

Westpac was down 1.80 per cent to $26.945 after reporting its first-half profit fell 22 per cent, while ANZ was down 0.40 per cent to $27.30, Commonwealth was down 0.53 per cent to $74.58 and NAB was down 0.19 per cent to $25.62.

Mining giant BHP was down 0.62 per cent to $36.71, Rio Tinto was down 0.78 per cent to $93.69 and Fortescue Metals was down 1.51 per cent to $7.19.

Some gold miners gained from the general uncertainty, with Northern Star adding 1.22 per cent to $8.27 and Evolution Mining gaining 3.42 per cent to $3.175.

Pharma giant CSL fell 0.61 per cent to $198.66 while medical supplier ResMed slid 2.15 per cent to $15.91.

Retail Food Group was down 6.67 cent after it acknowledged extending use-by dates on food products.

Bubs Australia jumped 12.83 per cent after the company announced a partnership with Fonterra Australia to produce a new line of organic infant formula.

The Aussie dollar is buying 69.81 US cents, from 69.95 US cents on Friday.