(Updates to close) May 4 (Reuters) - Australian shares fell on...

(Updates to close)

May 4 (Reuters) - Australian shares fell on Thursday as softer metal prices and technical selling drove miners and banks lower, pulling the index down for a third straight session.

The Australian was weakened by a strengthening in the U.S. dollar after the Federal Reserve kept U.S. rates unchanged and characterised weakness in the economy over the first quarter as temporary. [AUD/]

The S&P/ASX 200 index (xjo) closed 15.942 points, or 0.3 percent, lower at 5,876.4.

The 'Big Four' banks were the biggest drag on the index losing between 0.6 percent and 1.7 percent.

"Financials constitute almost half of the index. We're seeing a number of technical buy/sell programs hitting the market, and because of their index weighting, that's turning into direct pressure on financial stocks," said Michael McCarthy, chief market strategist at CMC Markets.

National Bank of Australia (NAB) reversed trend to end 0.5 percent lower after having gained as much as 2.2 percent earlier in the session. NAB had posted a 2.3 percent rise in half-year cash profit, beating analysts' estimates.

Miners in the region lost ground as Chinese iron ore posted its biggest single-day fall in more than five months, while London copper hit near two-week low. [IRONORE/] [MET/L]

Rio Tinto (RIO) and Fortescue Metals (FMG) fell 1.8 percent and 4.8 percent. BHP Billiton (BHP), however, crept up 0.1 percent.

New Zealand's benchmark S&P/NZX 50 index (nz50) was down 0.4 percent, or 27.43 points lower, at 7,378.41.

The financial and healthcare sectors fell as Westpac Banking (WBC) and Australia and New Zealand Banking (ANZ) declined 1.4 percent and 2 percent respectively, a third straight losing day.

Fisher & Paykel Healthcare (FPH) dropped 1 percent, while Ryman Healthcare (RYM) shed 1.4 percent.