Feb 13 (Reuters) - Australian shares declined on Friday, dragged down by commodity and healthcare stocks, while hearing-implants maker Cochlear tumbled as much as 16% on a weak annual forecast and weaker-than-expected first-half earnings.

The S&P/ASX 200 index .AXJO fell 0.8% to 8,975.80 points by 2318 GMT. The benchmark, which has gained 2% this week, is on course for its best week since April 2025.

It ended 0.3% higher on Thursday, its highest close since late October.

Cochlear COH.AX, one of Australia’s priciest stocks, was headed for its worst session since mid-March 2020 after flagging full-year earnings toward the low end of its forecast following a weaker-than-expected first half.

Stock was among the top drags on the benchmark as well as on the healthcare sub-index .AXHJ which fell 1.7%. The sub-index fell to its lowest level since late April 2019.

Westpac WBC.AX rose as much as 2.8% to a record high level after the banker reported a 6% rise in its first-quarter underlying profit, and was among the top gainers on the financials sub-index .AXFJ, which was up 0.3%.

Three of the "Big Four" banks rallied after delivering strong results, helping the sub-index gain 5.8% this week and put it on course for its best week since early March 2022.

Investors are now pivoting their focus to National Australia Bank NAB.AX>, which is slated to report earnings on Wednesday.

Among sub-indexes, miners .AXMM snapped their four-day winning streak, to fall 2.3% as iron ore and copper traded on weaker prices. MET/L IRONORE/

Top miners BHP Group BHP.AX, Rio Tinto RIO.AX and Fortescue FMG.AX fell between 0.8% and 1.3%. BHP and Rio Tinto will report their earnings next week.

Gold stocks .AXGD declined as much as 4.9%, snapping a four-day rally as bullion fell. [GOL/l]

Energy stocks .AXEJ fell as much as 1.6% on weak oil prices. O/R

In New Zealand, the benchmark S&P/NZX 50 index .NZ50 fell 0.8% to 13,421.88.

(Reporting by Sherin Sunny in Bengaluru; Editing by Rashmi Aich)

((Sherin.Sunny@thomsonreuters.com))