By Harshit Verma and Polina Devitt

LONDON Analysts and traders have lowered their price forecasts for platinum and palladium in 2024 due to weak auto production and concerns about a global economic slowdown, a Reuters poll showed on Wednesday.

The two sister metals are used primarily by automakers, which embed them in engine exhausts to reduce emissions. Platinum is also used in other industries, jewellery, and for investment.

The median forecast from a survey of 24 analysts and traders were for platinum to average $1,023 a troy ounce in 2024, down from $1,100 returned by a poll three months ago.

Platinum is down 14% so far this year after a rally in April-May when power outages and operational challenges in top producer South Africa inflated risk of limited supply and gold was soaring.

"Auto production has been softening recently, which has weighed on PGM (platinum group metals) prices and offset the positive impact on prices of falling output in South Africa," said Capital Economics analyst Caroline Bain.

"We expect the auto sector to start to pick up again in 2024, as interest rates start to fall globally, which should give a modest lift to prices."

For palladium, the poll forecast average prices of $1,250 an ounce in 2024 -- down from a forecast of $1,369 in the previous poll.

Palladium is down 38% so far this year and touched $1,083 last week, its five-year low, amid rapid rise of palladium-free electric vehicles and platinum for palladium substitution.

"Until there is a narrowing of the price differential between the two metals, there is little incentive for manufacturers to return to using palladium at the levels they once were," said David Russell at GoldCore.

(Reporting by Ashitha Shivaprasad and Polina Devitt; editing by David Evans)