JAKARTA- PT Pertamina and Saudi Aramco aim to finalise a deal in the first quarter of 2020 as they discuss a new plan for their joint venture, the Indonesian energy firm's chief executive said.

A plan to upgrade the Cilacap refinery in Central Java has been under discussion since 2016 but the two firms have failed to agree over pricing the project.

Their latest approach could see them form a joint venture company (JV) focused only on a planned additional facility at the site, CEO Nicke Widyawati said, instead of an initial plan that called for a JV that would involve all of the Cilacap facilities.

Pertamina would continue to operate the existing refinery and pay processing fees to the JV under the new plan under discussion, she said.

"This is what we are discussing now and we have set a target that in the first quarter next year this (negotiation) must be concluded," she said.

The expansion aims to increase Cilacap's refining capacity to 400,000 barrels per day from 348,000.

A Pertamina official in April said that if a deal with Aramco is not reached, the state-run company is prepared to launch the project on its own to meet its 2025 operational target.

Pertamina is also considering finding a new partner for its $10 billion refinery project in Bontang, East Kalimantan.

Pertamina signed a framework agreement in 2018 with Oman's Overseas Oil and Gas LLC (OOG) to develop a refinery and petrochemical complex in Bontang.

Widyawati did not elaborate on the reasons for looking for a new partner for the Bontang project.

(Reporting by Wilda Asmarini; writing by Fransiska Nangoy; editing by Jason Neely) ((Fransiska.Nangoy@thomsonreuters.com; +62 21 2992 7610; Reuters Messaging: fransiska.nangoy.thomsonreuters.com@reuters.net))