* Investors await RBA rate decision later in the day
* Financial index reverses losses, CBA extends its gains
* NZ led higher by a2 Milk Company
By Devika Syamnath
June 5 (Reuters) - Commodity-related stocks led the Australian benchmark index lower on Tuesday, though losses were partially offset by Commonwealth Bank's extended gains after it settled a civil lawsuit filed by financial intelligence agency AUSTRAC.
At 0228 GMT, the S&P/ASX 200 index .AXJO was down 0.3 percent, or 18.5 points at 6,007. The benchmark rose 0.6 percent on Monday.
Australia's central bank will announce a decision on its cash rate later in the day. It is seen holding rates at record lows until March, according to a Reuters poll. stocks declined on weak metal prices, notably iron ore, while a sharp overnight fall in global oil prices hurt energy shares, sending the sector index .AXEJ as much as 1.5 percent lower. MET/L IRONORE O/R
Global mining heavyweights Rio Tinto (LON:RIO) RIO.AX and BHP Billiton (LON:BLT)'s BHP.AX fell 2.1 percent and 1.5 percent respectively, and their declines were the biggest drags on both the metals and mining index and the Australian benchmark.
Gas supplier Origin Energy ORG.AX lost up to 3 percent, touching its lowest in more than one month, while Woodside Petroleum WPL.AX shed 1.1 percent.
Australia's largest bank by market capitalization CBA's CBA.AX rose as much as 1.4 percent, helping the financial index .AXFJ reverse earlier losses.
The bank's shares gained 1.7 percent on Monday despite being pinned with a record A$700 million penalty to settle money laundering charges by AUSTRAC, as investors were relieved authorities had not prescribed larger fines. stocks .AXHJ , which hit a record on Monday, traded lower. CSL Ltd CSL.AX dropped 0.7 percent and Ramsay Health Care RHC.AX fell 4.1 percent to its lowest level in over two years.
Strength in U.S. Treasury yields depressed real estate stocks such as Mirvac Group MGR.AX and Scentre Group SCG.AX which dropped 3.7 percent and 1.9 percent, respectively.
At 0226 GMT, New Zealand's benchmark S&P/NZX 50 index .NZ50 climbed 1 percent, or 82.84 points, to 8719, its best in three weeks.
The index enjoyed broad gains led by dairy producer A2 Milk Company ATM.NZ , which added as much as 4.3 percent.
Fellow dairy products maker Fonterra Co-Operative Group FCG.NZ rose about 1 percent after it said total domestic milk production in April rose 3 percent.