State-owned gas firm Perusahaan Gas Negara (PGN) plans to finalize the acquisition of 51 percent of Pertagas, a subsidiary of state-owned oil and gas holding company Pertamina, in December, three months behind the initial deadline.

Pertamina investment planning and risk management director Heru Setiawan told journalists on Thursday that the delay was due to ongoing due diligence and the final audit of Pertagas.

"We also recalculated the valuation, as we also have to consider the value of Pertagas' subsidiaries, which are part of the deal," he said.

Based on the previous valuation, PGN would have to prepare US$1.2 billion for the Pertagas deal, which included the purchase for Pertagas subsidiary PT Pertagas Niaga (PTGN).

The new valuation will also include other Pertagas subsidiaries: Perta-Samtan Gas, Perta Arun Gas, Perta Daya Gas and Perta Kalimantan Gas.

Previously, PGN corporate secretary Rachmat Utama said the option to take the remaining Pertagas subsidiaries was open and that PGN would consider the future prospects of the subsidiaries. He said PGN also considered to merge those subsidiaries into one company. (bbn)