The Standards in Public Office Commission investigation into alleged duplication of expenses claims by Fianna Fáil senator Brian Ó Domhnaill may resume in the autumn.

The investigation has been on hold for three years since Mr Ó Domhnaill launched a legal challenge that argued, among other things, that the commissioners hearing the case should be bilingual, and should not have to rely on interpreters to understand the proceedings in Irish.

Facilities had been put in place to allow simultaneous translation for the hearing before the Sipo Commissioners.

The complaint against Mr Ó Domhnaill relates to alleged duplication of expenses claims when he was a member of Údarás na Gaeltachta and Donegal County Council.

They relate to the period before he became a senator in 2007.

Last week the Court of Appeal rejected arguments that there was a requirement that the Commission members hearing the complaint should be bilingual.

It also did not agree with Mr Ó Domhnaill's contention the complaint was anonymous. The court held that while the initial disclosure was anonymous the substantive complaint made to the Commission had been made by the Mayor of Donegal County Council, as well as the county manager.