* Aussie benchmark closes at 21-month low
* Slump in oil prices sends energy stocks to 8-month low
* Miners hit 4-week low on soft iron ore prices
* Financials pare losses to end slightly higher (Updates to close)
By Rashmi Ashok
Nov 21 (Reuters) - Australian shares closed at their lowest level since February 2017 on Wednesday as worries of slowing global growth and a plunge in oil prices triggered a global equity sell-off.
The S&P/ASX 200 index .AXJO clawed back some early losses but still closed 0.51 percent or 29.00 points lower at 5,642.800. The benchmark fell 0.4 percent on Tuesday.
Miners .AXMM were the biggest drag on the index, dropping 2.9 percent to four-week low after iron ore prices DCIOcv1 fell 1.8 percent. IRONORE/
Global miner BHP BHP.AX and its rival Rio Tinto (LON:RIO) Ltd RIO.AX both tumbled by 3.3 percent each.
Weighed by the plunge in oil prices on Tuesday, energy stocks .AXEJ slumped 2.5 percent to an 8-month low. O/R
Even though oil recovered some of the losses on Wednesday, overall market weakness remained little changed. Shares of Woodside Petroleum Ltd WPL.AX fell 2.1 percent, while Santos Ltd STO.AX tumbled 4.4 percent.
However, financial stocks .AXFJ recovered late in trade to inch up, with Commonwealth Bank of Australia, the country's top lender, gaining 1.2 percent and National Australia Bank Ltd NAB.AX rising 0.7 percent.
"The big banks are a safe bet in troubled waters... their underlying profit remains very strong. When we see buying come into the market, it tends to come through CBA to begin with... because of its large exposure to the domestic market," said James McGlew, executive director of corporate stockbroking at Argonaut.
McGlew added that sanity seemed to return after the initial selling, saying "CBA is always seen as the safest bet amongst them, and they're all at a point where the price and dividend yield is too attractive to ignore."
The healthcare index .AXHJ , a defensive sector which benefits during uncertain periods and broader sell-offs, rose 1.5 percent at close.
Sector heavyweight CSL Ltd CSL.AX rose 1.7 percent and Cochlear Ltd COH.AX firmed 2.3 percent.
New Zealand's benchmark S&P/NZX 50 index .NZ50 slipped 0.55 percent or 47.9 points to finish the session at 8,672.400.
Dairy giant a2 Milk Co Ltd ATM.NZ fell 3.4 percent at close and was among top drags on the main index.
But online marketplace operator Trade Me Group TME.NZ closed 16.3 percent higher after a takeover offer by private equity player Apax Partners.