RH Petrogas Limited was formerly known as Tri-m Technologies (S) Ltd., which was incorporated in April 1987 under the name of Auto-Assem Computer (Singapore) Pte Ltd. In September 1987, the company changed its name to Tri-M Technologies (S) Pte Ltd.

Tri-M was formed as a three-party joint venture between Mitsubishi Corporation, Miyoshi Electronic Corporation and Greendale Investments Pte Ltd to provide contract manufacturing services. In 1993, the company was successfully listed on the Singapore Stock Exchange. In January 1997, Mitsubishi and Miyoshi sold their interest in the company to Woodsville Pte Ltd. Woodsville Pte Ltd is a company incorporated in the British Virgin Islands and is beneficially owned by Tan Sri Datuk Sir Tiong Hiew King (Executive Chairman of Tri-M) and Dato' Sri Dr Tiong Ik King (Executive Director of Tri-M). The principal business of Woodsville is that of an investment holding company; it is the holding company of Surreyville Pte Ltd.

Tan Sri Datuk Sir Tiong Hiew King and Dato' Sri Dr Tiong Ik King are brothers. The Tiong family owns the Rimbunan Hijau Group of Companies. The Group is a multi-national conglomerate with operations in Malaysia, the PRC, Papua New Guinea, Australia and New Zealand. Its principal business activities include timber harvesting, processing, marketing, agricultural plantations, newspaper publishing, insurance, banking, property development and shipping. The Rimbunan Hijau Group employs around 30,000 employees and has an estimated annual turnover of over US$1 billion.

As at 17 August 2009, Surreyville Pte Ltd and Sharptone Investments Limited own 50.56% and 28.03% of the Company respectively, while the public shareholders account for the remaining 21.41%.

The Company changed its name to RH Petrogas Limited on 25 November 2009.