JAKARTA, Oct 20 (Reuters) - The first trading began on Friday on Indonesia's palm oil exchange, part of an effort by the world's biggest producer of the vegetable oil to create credible benchmark prices.

Four lots of 25 metric tons of physical crude palm oil (CPO) traded on Friday at 11,305 rupiah ($0.7130) per kg when the Indonesia Commodity and Derivatives Exchange (ICDX) opened, an ICDX official said. The shipments are for delivery to the port of Dumai in Sumatra in 15 days.

Friday was the first day that the ICDX offered spot pricing and 18 companies were expected to participate, exchange CEO Nursalam told Reuters.

Futures contracts for CPO will be offered later, said Nursalam, who has a single name like many Indonesians.

The exchange is providing three trading sessions daily, said a second ICDX official.

"The main point is the exchange will create a transparent and organized trade," said Didid Noordiatmoko, head of Indonesia's commodity trade regulator BAPPEBTI.

Indonesia is targeting for the market to form a reference price by the first quarter of next year to rival those in Kuala Lumpur and Rotterdam.

The trade through the exchange is currently voluntary. Most Indonesian palm oil exporters typically trade directly with buyers. ($1 = 15,855.0000 rupiah) (Reporting by Dewi Kurniawati; Additional reporting by Bernadette Christina; Writing by Fransiska Nangoy; Editing by Subhranshu Sahu and Christian Schmollinger)