The Irish Competition and Consumer Protection Commission has launched a formal investigation in the emissions scandal at Volkswagen.

The commission says it is deeply concerned by the understatement of carbon dioxide emissions in cars distributed in Ireland.

It says consumers may have been influenced by information - which is now believed to have been inaccurate - when looking at buying any of the cars affected.

At least 9,000 of the vehicles are estimated to be in Ireland.

The commission says the investigation will establish whether there has been a breach of Irish consumer protection law.

Commission Chair Isolde Goggin said, "we are committed to obtaining the best outcome for Irish consumers and ensuring that they do not suffer as a consequence of being provided with misleading information".

Earlier this week it was reported that Volkswagen has contacted the Irish Government warning that extra tax payments may be due on cars affected by the company's emission test cheating scandal.

In a letter to Finance Minister, Michael Noonan, the company's chief executive, Matthias Müller revealed that the incorrect CO2 values registered by its vehicles in test conditions, "could affect taxes or other public charges already assessed or to be assessed."

He added that Volkswagen will meet the cost of any increase in the tax liability on these diesel vehicles.