(Updates to close)
Aug 23 (Reuters) - Australian shares posted modest losses on Wednesday after poor results from Insurance Australia Group IAG.AX and Healthscope Ltd HSO.AX dragged down the healthcare and financial sectors, while Commonwealth Bank of Australia CBA.AX slipped on the threat of a new lawsuit.
The S&P/ASX 200 index .AXJO ended down 12.92 points, or 0.2 percent, at 5,737. The benchmark rose 0.4 percent on Tuesday.
Financial and healthcare stocks accounted for more than half the losses.
Insurance Australia Group, the country's biggest general insurer by market share, tumbled 8 percent to close at its lowest in more than three months.
Commonwealth Bank of Australia ended the session 0.6 percent down at its lowest more than two months.
In the latest headache for Australia's biggest listed company, a law firm on Wednesday threatened to file a class action suit against it for allegedly failing to disclose that it was facing money-laundering charges. operator Healthscope Ltd HSO.AX was the biggest loser among healthcare stocks, ending the day 15.1 percent lower after it reported a 9.2 percent drop in full-year net profit. metals and mining index .AXMM was down 0.1 percent despite modest gains for global mining giants BHP Billiton (LON:BLT) BHP.AX and Rio Tinto (LON:RIO) RIO.AX .
On the other end, energy stocks finished higher with the Australian energy index .AXEJ closing 1.4 percent up.
Australia's top power and gas retailer Origin Energy ORG.AX closed 2.8 percent higher and oil major Woodside Petroleum WPL.AX closed up 1.1 percent.
New Zealand's benchmark S&P/NZX 50 index .NZ50 crept up 0.2 percent, or 12.38 points, to a record closing high of 7,879.46.
Consumer staples was the biggest boost, helped by Dairy firm a2 Milk Company ATM.NZ which gained nearly 6 percent.
Elsewhere, the New Zealand Treasury reduced its economic growth forecast for the year to June, and cut its growth projection for the year to June 2018 in the May budget update.