* Healthcare sector among top drags on ASX 200
* Rio Tinto (LON:RIO) rises on plans to shut NZ aluminium smelter
* NZ50 marks has biggest intraday drop in over 1 month
By Ambar Warrick
Oct 23 (Reuters) - Australian shares slipped on Wednesday as investors locked in profits in the healthcare sector, while a weaker Wall Street also prompted some selling.
The S&P/ASX 200 index .AXJO was down 0.3% or 21.50 points to 6,650.70 at 0047 GMT. The benchmark rose 0.3% on Tuesday.
U.S. stocks fell on Tuesday after British lawmakers rejected the government's proposed timetable for passing legislation to ratify Brexit. Markets fear the perceived impact to the global economy from a messy Brexit process. .N
In Australia, healthcare stocks were among the worst performing sectors early Wednesday, with the subindex .AXHJ shedding about 1%. Buying of defensive stocks has pushed the sector up nearly 30% this year, making it one of the best performers on the ASX 200.
"It's simply a bit of profit-taking or rebalancing of portfolios right now in the health space," said Brad Smoling, managing director at Smoling Stockbroking.
CSL Ltd CSL.AX , the largest stock in the sector and fourth-largest on the ASX 200 by market capitalization, was down about 0.9%. The stock touched a record high last week, and through Tuesday was up 9% this month.
Financial stocks .AXFJ fell about 0.5%, tracking their peers on Wall Street .SPSY . The country's Big Four banks were about 0.3% to 0.7% lower.
Gold stocks .AXGD rose 0.3%, as bullion prices benefited from increased tensions over Brexit. GOL/
Global miner Rio Tinto RIO.AX climbed 0.5% after it flagged a possible pullback or closure of an "unprofitable" aluminium smelter in New Zealand. Gold Road Resources Ltd GOR.AX rose 12% and was the largest gainer on the ASX 200 after RBC upgraded the stock.
New Zealand shares had their biggest intraday drop since early September, as major electricity sellers were stung by Rio Tinto's plan to shut its aluminium smelter.
The benchmark S&P/NZX 50 index .NZ50 fell 1.5% or 164.31 points to 10,926.08.
Meridian Energy Ltd MEL.NZ slid nearly 8% and was the worst performer on the New Zealand benchmark. The company is the main supplier of electricity to the Rio Tinto smelter, which is New Zealand's biggest power consumer.
Other energy retailers Contact Energy Ltd CEN.NZ and Mercury NZ Ltd MCY.NZ fell 7.3% and 5.7%, respectively.