KUALA LUMPUR, Nov 18 (Reuters) - Malaysia's Sime Darby Plantation Berhad reported a 73% jump in third-quarter net profit on Thursday, buoyed by higher palm oil prices but flagged that prices were likely to decline next year.

Profit for the July-September period rose to 610 million ringgit ($145.93 million) from 190 million ringgit a year earlier, while revenue rose 39% to 5.06 billion ringgit.

A continuous upward trend in palm oil prices and higher oil extraction rate more than compensated for a drop in production, Sime Darby, the world's largest oil palm planter by land holdings, said in an exchange filing.

Malaysian plantations have suffered from a severe labour crunch exacerbated by pandemic-induced border closures, which cut production and lifted benchmark crude palm oil prices to record highs.

But the high prices will help compensate for the impact of labour shortages, the firm said.

Malaysia last month approved the entry of 32,000 migrant workers for the palm oil sector to help reverse the production slump.

Sime Darby said it expected palm oil prices to remain elevated at least until the end of the year before a possible downward adjustment in the second quarter of 2022 when supplies are anticipated to improve.

Demand is expected to remain strong as more countries ease their COVID-19 restrictions, it said.

"The pandemic has certainly put a spotlight on the critical need to accelerate the mechanisation, automation and digitalisation of plantation operations, to reduce dependence on manual labour," Managing Director Mohamad Helmy Othman Basha said.

The company is spearheading this reinvention of plantation operations, he added.

Sime Darby expects an overall strong financial year performance for 2021.

($1 = 4.1800 ringgit)

(Reporting by Mei Mei Chu; Editing by Rashmi Aich)