* Biotech co Mesoblast top drag on the benchmark
* Energy sub-index hits its lowest since April 22
* Tech index is the sole gainer among indexes, up 2.2%
By Arundhati Dutta
Oct 2 (Reuters) - Australian shares fell on Friday, dragged by losses in energy stocks after an overnight tumble in oil prices, while a near 45% plunge in biotech firm Mesoblast Ltd MSB.AX also weighed on the benchmark.
The S&P/ASX 200 index .AXJO fell up to 0.8% to 5,824.1 in early trade and was on track for a weekly drop of 2.5%. The benchmark had closed 1% higher on Thursday.
Mesoblast hit its lowest since late-April and was the top percentage loser on the benchmark after the U.S. Food and Drug Administration demanded more proof that its flagship drug worked.
Meanwhile, an overnight plunge in oil prices knocked the energy sub-index .AXEJ down 2.5% to its lowest since April 22.
Shares of Beach Energy BPT.AX and Oil Search OSH.AX were the top percentage losers, both losing around 2%
Mining stocks .AXMM dropped as much as 2.2%, hitting their lowest in nearly three months. Heavyweights BHP Group BHP.AX and Rio Tinto (LON:RIO) RIO.AX shed up to 2.9% and 1.7%, respectively.
Financials .AXFJ declined as much as 1.1% to their lowest in a week.
The tech index .AXIJ , the only sub-index to trade in the positive territory, advanced 2.2% and hit a one-month high. Gains in Wisetech Global WTC.AX , up 5.7%, and Afterpay's APT.AX 3.7% rise boosted the index.
In New Zealand, the benchmark S&P/NZX 50 index .NZ50 was down 0.1% at 11,795.99 by 0110 GMT.
The top percentage gainer on the benchmark was Serko Ltd SKO.NZ , up 6.7%, while the top percentage loser was Vista Group International Ltd VGL.NZ , down 3%.