Legal representatives for Volkswagen have absented themselves from proceedings being taken against the company at Castlebar District Court.
A Roscommon motorist is seeking compensation after the car maker admitted cheating on emissions tests last year.
This afternoon, Volkswagen's legal team walked out of the court after a judge ruled the case would proceed.
Last year hundreds of thousands of cars with Volkswagen engines were recalled.
It followed the company's admission that it had installed software in diesel cars to trick emissions testers in the United States.
Eithne Higgins of Croghan, Boyle, Co Roscommon, contends that there may be implications in respect of Vehicle Registration Tax or road tax, as a result of incorrect emissions data.
When her action against Volkswagen resumed today, the company's barrister, Paul Fogarty, questioned the court's jurisdiction to hear or determine the case.
He told Judge Mary Devins that no company representatives were attending the hearing and that his clients would proceed by way of a judicial review, should the case go on.
He described the proceedings as "utterly unsatisfactory, unfair and inappropriate".
The claimant's solicitor, Evan O'Dwyer, said this was the latest in a series of attempts by Volkswagen to obstruct the process.
He pointed to delays in furnishing documentation and said the company had engaged in systematic bullying of Mrs Higgins, her legal team and the ourt itself.
Mr O'Dwyer said the car maker had demonstrated "abject contempt" for the process.
Judge Devins pointed out that Volkswagen had not appealed her jurisdiction or any orders in connection with the case in recent months.
When she said she would proceed to hear the case, Mr Fogarty and his instructing solicitors walked out of the court.
In his evidence, American attorney Michael Lehmann said there was a huge difference in the way the company was dealing with the emissions issue in different jurisdictions.
He said the firm seemed be engaged in a war of attrition with European customers but had been more cooperative with US motorists.
Emissions expert Calvert Stinton questioned the effectiveness of the remedies being offered by Volkswagen on affected vehicles.
He also said carbon dioxide and oxides of nitrogen emissions were intimately related. This was something at issue earlier in the proceedings
A view from Nobel Prize winning economist Professor Joseph Stiglitz on the resale value of impacted vehicles was also read into the record before the financial implications of the incorrect data were outlined.
Oxford based economist Robin Noble said there must be a Volkswagen analysis of the likely financial implications of the emissions issue.
He also spoke about "brand value" of the vehicles. Mr Noble said cars impacted by the incorrect data would be less trusted by motorists in future and it would be interesting to see what kind of information or research VW had conducted in this regard.
Proceedings will resume in the morning.