The man who investigates electoral fraud in Canada says some investigations will simply "abort" if he isn't given the power to compel testimony from witnesses.

Yves Cote, the commissioner of elections, provided another direct critique of the Conservative government's electoral reform bill in testimony to a parliamentary committee.

Cote says the government is making a mistake by separating his office from Elections Canada, saying it will slow down investigations and goes against principles established by regulatory bodies such as the Canada Revenue Agency and the Competition Bureau.

He says he was never consulted on the proposed move. Bill C-23, dubbed the Fair Elections Act by the Harper government, has been roundly criticized by current and former chief electoral officers, elections experts in Canada and abroad and by newspaper editorials across the country.

Testimony eagerly anticipated

Cote's testimony was eagerly anticipated because the Conservatives insist they are giving him new independence by moving Elections Canada's enforcement arm into a separate bureaucracy overseen by the attorney general, a cabinet minister.

Cote insisted otherwise, and said the failure to give him powers to compel testimony that are held by other regulatory agencies will stop some investigations.

He said witnesses have already refused to co-operate with him "including in matters of some significance."

An investigation into fraudulent robocalls during the 2011 election are still unresolved, although a single junior Conservative party staffer in Guelph, Ont., has been charged with some related offences.