Jakarta, Indonesia - Indonesian telecom firms were mulling appeals on Thursday after the competition watchdog found them guilty of price fixing and raking in hundreds of millions of dollars from illegal text message charges.

The Business Competition Supervisory Commission (KPPU) found six telecommunications companies guilty of collusion and slapped five of them with fines worth some US$10 million (S$13.7 million).

The KPPU said on Wednesday the companies had formed a cartel that set tariffs for short messages services (SMS).

They included state-owned PT Telkomsel, which is also 35 per cent owned by Singapore Telecommunications Ltd, and the mobile phone firm of welfare minister Aburizal Bakrie.

'The six companies caused around 2.8 trillion rupiah (S$413.3 billion) in potential losses for their customers.' He said the six firms - PT Telekomunikasi Indonesia, PT Telkomsel, PT Excelcomindo Pratama, Bakrie Telecom, PT Mobile-8 and SMART Telecom - had 14 days from Wednesday to file an appeal in the Jakarta district court.

The commission ordered Telkomsel and Excelcomindo to pay fines of 25 billion rupiah each. Telkom, Mobile-8 and Bakrie Telecom were fined 18 billion, five billion and four billion rupiah respectively.

SMART Telecom was not fined as it was considered a new member of the market.

PT Telkomsel President Director Kiskenda Suriahardja rejected the findings which he said had no 'permanent legal standing.'

'The company has never been involved in any cartel nor price fixing,' he told AFP.

'As this decision has no permanent legal standing we are considering taking legal action to find explanations and legal certainty.'

Telkomsel lawyer Ignatius Andy earlier told reporters that the KPPU 'doesn't have evidence that supports its verdict.'

Excelcomindo President Director Hasnul Suhaimi told Dow Jones Newswires that 'we are going to study the verdict before deciding to make an appeal.'

Excelcom has around 13 million mobile subscribers in Indonesia, representing a market share of approximately 14 percent as of September last year.

Telkomsel, which has about 50 per cent of the market, and Excelcomindo are two of the three biggest mobile operators in the Southeast Asian country along with Indosat. -- AFP