* Benchmark's biggest weekly decline since Nov. 16
* Investors fret over global economy outlook ahead of four-day weekend
* New Zealand's 3rd straight week in the red (Updates to close)
By Nikhil Subba
Dec 21 (Reuters) - Australian shares suffered their biggest weekly loss in over a month on Friday, as investors stampeded out of riskier asset markets on heightened anxiety over faltering global growth prospects.
A plunge in oil prices and the threat of a U.S. government shutdown added to the gloom even as investors struggled to come to terms with the U.S. Federal Reserve's plan to keep raising rates despite increasing risks to growth.
That left the S&P/ASX 200 index .AXJO in bad shape ahead of the Christmas break. The index fell 0.7 percent, or 38.20 points, to close at 5467.60, and was off 2.4 percent for the week - the worst performance since the week-ended Nov 16.
A partial U.S. government shutdown loomed large over the Christmas break after President Donald Trump informed House Republicans he would refuse to accept a stop-gap measure that doesn't include funds for his long-promised border wall. sentiment is still quite uncertain about what's happening with the Fed and what's happening in the trade deal (with China), so till those get clarified, the markets will be a bit edgy", said Mathan Somasundaram, market portfolio strategist at Blue Ocean Equities.
"Nobody is going to be brave enough to take any big position going into the long weekend."
Financial stocks, which account for over a third of the benchmark index weight, led losses with the financial index .AXFJ down 1.2 percent for its third straight week in the red.
The 'Big Four' were a major drag; Westpac Banking Corp WBC.AX fell 1 percent and National Australia Bank NAB.AX fell 1.1 percent, both touching their lowest in more than six years.
Commonwealth Bank CBA.AX declined 0.6 percent to a one-month low, while Australia & New Zealand Banking Group ANZ.AX closed 1.1 percent lower to its lowest in over two years.
Energy stocks continue to be battered by uncertainty over future energy demand amid worries of an economic slowdown heading into next year.
Oil refiner Caltex Australia Ltd CTX.AX fell 1.7 percent, while index heavyweight Santos Ltd STO.AX was down 0.2 percent, earlier falling to its lowest since March end.
A rise in copper and Chinese steel prices boosted the metals and mining index .AXMM 1.4 percent higher, in its third straight week of gains.
The index was lifted by mining giants BHP Group BHP.AX which climbed 2.3 percent, and Rio Tinto (LON:RIO) RIO.AX which advanced 0.7 percent.
New Zealand's benchmark S&P/NZX 50 index .NZ50 fell 1 percent to finish the session at 8686.19, and declined 0.4 for the week, its third consecutive week of losses.
Health products maker Comvita Ltd CVT.NZ dropped 9.1 percent to its lowest in over three years, while payments provider Pushpay Holdings Ltd PPH.NZ declined 6.7 percent to its lowest since Nov. 27, both among top losers on the benchmark.