Indonesia's state-owned energy firm Pertamina has signed Memoranda of Understanding (MoUs) with Chinese, Japanese and Saudi energy firms as part of a $25 billion drive to upgrade five of the former Opec member's refineries.

President Joko Widodo, who took office seven weeks ago, is looking to modernise the country's refineries and build new ones as part of sweeping energy reforms aimed at curbing corruption and meeting ballooning energy demands.

Pertamina, whose entire board of directors was replaced last month as part of Widodo's energy reforms, signed MoUs on Wednesday with the China Petroleum and Chemical Corporation (Sinopec), Saudi Aramco and Japan's JX Nippon Oil & Energy Corporation to help with refinery upgrades.

Under the MoUs, the firms will first assess the feasibility of the upgrades. Pertamina hopes to sign more binding agreements within six months, Pertamina chief executive Dwi Soetjipto told reporters at a media event.

"(The upgrades) will be completed in around four years and there will also be a growth in demand so this alone won't be enough to fill the demand gap," Soetjipto said, adding that Pertamina was also looking at building new refineries.

Indonesia's Refinery Development Master Plan aims to double the country's crude processing capacity to 1.68 million bpd from 820,000 bpd at present, Soetjipto said.

"We are aware that if we don't fill this gap it will widen," he said.

According to data provided by Pertamina, the plan aims to more than triple gasoline output from Indonesia's refineries to 630,000 bpd by 2025 from 190,000 bpd in 2012, and more than double diesel output to 770,000 bpd by 2025 from 320,000 bpd in 2012.-Reuters