An Oireachtas inquiry into cost overruns on an Iarnrod Eireann signalling system may be televised on TG4, the Irish language channel.

Members of the Oireachtas Joint Committee on Public Enterprise and Transport want to find out how a contract with Modern Networks has already cost £25£40 million, despite an initial valuation of £14 million.

The committee will have power to compel witnesses to attend its hearings, which will be similar to the Dail Committee of Public Accounts examination in 1999 of DIRT evasion by the State's banks.

Teilifis na Gaeilge, as TG4 was then known, broadcast that investigation live.

Of the signalling inquiry, its leascheannasai, Mr Padhraic O Ciardha, said: "We are constantly looking at the possibility of providing live coverage. The PAC coverage in September 1999 worked very well."

Morning hearings during summer would be easier to televise, he added.

In addition to the cost overruns, the committee will investigate how four Iarnrod Eireann figures who worked on the signalling project left the State company to join Modern Networks.

A PricewaterhouseCoopers examination of the contract said it failed to meet any of the rail firm's procurement objectives.

Organising television coverage of such hearings is said to be complex because programming is integrated into existing schedules. From a fairness perspective, broadcasters have an obligation to cover such hearings in full.

This means schedules could be disrupted if public meetings ran over their allotted time.

The channel is thought to have approached the Moriarty and Flood tribunals seeking to televise their hearings, but it was not successful.