* GDP growth exceeds expectations
* Banks limit gains after cartel charges against ANZ
* Healthcare stocks close at record (Updates to close)
June 6 (Reuters) - Australian shares posted broad-based gains led by mining stocks on Wednesday but banks fell after the country's competition watchdog laid charges against top lender Australia and New Zealand Banking ANZ.AX for alleged cartel behaviour.
The S&P/ASX 200 index .AXJO ended 0.5 percent higher or 30.2 points to 6,025.1. The benchmark closed 0.5 percent lower on Tuesday.
Sentiment was helped by data showing Australia's economy grew at its fastest annual pace in almost two years, with 3.1 percent growth in the March quarter. were the star performers with mining stocks .AXMM rising 1.8 percent, supported by strength in global iron ore and metal prices. MET/L IRONORE/
Bloomberg cited sources saying bids from a consortia of bidders valued BHP's BHP.AX shale unit at up to $9 billion. heavyweights BHP Billiton (LON:BLT) Ltd BHP.AX and Rio Tinto (LON:RIO) Ltd RIO.AX each closed about 2 percent and 2.5 percent firmer.
Meawhile, biotherapeutics company CSL Ltd CSL.AX surged to a record close to provide the second biggest boost to the main board.
As of Tuesday's close, CSL's stock had added over 30 percent to its value so far this year, in stark contrast with the main index .AXJO which gave up over 1 percent.
Energy stocks like Woodside Petroleum WPL.AX and Origin Energy ORG.AX rose 2.8 percent and 3.1 percent, respectively, both benefitting from stronger oil prices. O/R
However, bank stocks .AXFJ declined 0.8 percent, as the market regulator said after the market's close on Tuesday that ANZ had been charged with cartel behaviour. and National Australia Bank NAB.AX both saw their weakest close in well over a year while Westpac Banking WBC.AX closed at its lowest since 2013.
New Zealand's S&P/NZX 50 index .NZ50 was up 0.6 percent or 56.41 points to 8813.45 and closed at yet another record after having marked one in the previous session.
Healthcare stocks contributed most of the gains with Fisher & Paykel Healthcare FPH.NZ extending gains to a fifth session and ending at a record.