Mr Lowry says his bill for representation at the tribunal, which lasted 14 years, will run into millions, the High Court heard.
He claims he was discriminated against, compared to the other subject of the tribunal, the late former taoiseach Charles Haughey, who was awarded 100% costs.
The Independent Tipperary North TD has brought the legal challenge over the October 2013 tribunal decision which awarded him only one-third costs after finding he failed to fully co-operate with it.
Opening the tribunal’s opposition to Mr Lowry’s application yesterday, Shane Murphy SC said Mr Lowry’s claims do not stand scrutiny.
The decision on costs was arrived at after “a very elaborate process” and all fair procedures were observed, counsel said.
Mr Lowry was given the opportunity to make submissions on costs and did so, counsel said.The costs decision was made with reference to the findings in a report on Mr Lowry’s conduct rather than the substantive findings of the tribunal.
The hearing before Mr Justice John Hedigan resumes next week.