By Swati Pandey and Rebecca Howard
SYDNEY/WELLINGTON, June 24 (Reuters) - Australian shares tumbled as much as 2.7 percent on Friday amid wild gyrations in global markets as voting results suggested a higher likelihood of Britain exiting from the European Union.
The S&P/ASX 200 index .AXJO skidded 67.18 points to a one-week low of 5,213.5 by 0155 GMT, its biggest intra-day percentage drop since Feb.9. The benchmark closed 0.2 percent higher on Thursday at 5,280.70.
"If it's a Leave win, we're gonna re-evaluate everything," said OptionsXpress analyst Ben Le Brun.
"Obviously, the risk sentiment will be very bad, we'll see downward impact on the Aussie dollar, we'll see downward impact across the share market and it will probably filter through to our economy a little bit later on. But the knee-jerk reaction will be negative."
Early official results showed the margins were nail-bitingly tight causing carnage in world markets on Friday. 171 of 382 counting areas declared, the Leave camp was put at 51.3 percent against 48.7 percent for "Remain".
Australian shares witnessed a broad-based sell-off with all sectors trading in the red, led by banks and resources.
Financial companies with direct exposure to the United Kingdom were the hardest hit - Henderson Group HGG.AX , CYBG Plc CYB.AX and Genwotrth GMA.AX slumped 4.7 to 7 percent.
ANZ Banking Group ANZ.AX led falls among the "Big Four" lenders, dropping 2.2 percent while Commonwealth Bank CBA.AX , Westpac WBC.AX and National Australia Bank NAB.AX were down nearly 2 percent. Macquarie Group MQG.AX slipped over 4 percent.
Major miners BHP Billiton (LON:BLT) BHP.AX and Rio Tinto (LON:RIO) RIO.AX skidded 4 percent and 3 percent respectively. Fortescue FMG.AX slipped 4.5 percent. Energy companies Woodside WPL.AX and AGL Energy AGL.AX fell 2.6 percent each.
Gold miners, on the other hand, rose smartly with Newcrest NCM.AX up 1.5 percent while Oceanagold OGC.AX and Northern Start NST.AX adding about 1.2 percent each.
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NEW ZEALND
New Zealand's benchmark S&P/NZX 50 index .NZ50 fell 0.5 percent or 31 points at 6,790.51 Friday on very light volumes as investors stuck to the sidelines as results rolled out from Britain.
Both Australia and New Zealand would likely extend losses on Monday if the Leave camp prevails, while a Remain vote would turn sentiment around, said associate director for Macquaire Prive Wealth Rob Gwyther.
The biggest gainers on the NZX included Ebos Group EBO.NZ , up 0.9 percent while the biggest losers included a2 Milk ATM.NZ , down 5.5 percent. Volumes are tepid across the market, said Gwyther.
(Editing by Kim Coghill)