The Australian stockmarket ended Wednesday with its strongest in over four months, bolstered by regional markets and with National Australia Bank and gold miners posting solid gains.

At the close, the benchmark S&P/ASX200 Index added 35 points or 0.8 per cent to 4661.5. The broader All Ordinaries Index was 33.6 points or 0.7 per cent higher at 4702.7.

Among the sectors, materials and financials had both put in 1 per cent, while a new record gold price saw gold shares climb 1.7 per cent.

The Australian bourse received a boost from the Japanese sharemarket, where the Nikkei strengthened 2.3 per cent after the government intervened to weaken the yen. Toyota Motor Corp and other exporters soared on the news.

Finance Minister Yoshihiko Noda today confirmed the intervention, saying Tokyo was also discussing with authorities overseas. The greenback had hit a 15-year-low at 82.87 yen earlier in the day but was at 84.78 yen by noon.

Wednesday's trading trends showed a mixed mood among local investors, according to EL&C Baillieu Stockbroking director Richard Morrow.

''It suddenly took off in the mid-afternoon in reaction to global trends," he said.

''It sort of suggests to us that there's indecision out there about the direction - we seem to be on a bit of a knife edge.

National Australia Bank led gains among the big four, climbing 2.85 per cent to $25.94 after abandoning its agreement with AXA SA to acquire the Australian and New Zealand businesses of AXA Asia Pacific.

Westpac climbed 26 cents or 1.1 per cent to $23.63. ANZ firmed 14 cents or 0.6 per cent to $24.16 and Commonwealth Bank looked up 20 cents at $53.80.

Resources stocks were moved past the flat midday trading by the close of trade.

BHP Billiton grew 0.99 per cent to $39.44 after takeover target Potash Corp said it was not considering a large stake sale to a third party or long-term production sharing agreements to block the miner's hostile bid.

Its rival Rio Tinto added 15 cents to $75.30 following announcement that its production at Laterriere Works aluminium smelter in Quebec will resume completely in a couple of weeks after a power outage.

Gold major Newcrest ended 1.28 per cent or 50 cents higher at $39.50 after gold surged more than two per cent overnight to a record above $US1,270 an ounce, its biggest one-day gain in four months.