Mark McCall, chair of the Electric Vehicle Association of Northern Ireland, said members had already questioned how miles driven outside the UK would be measured.
Mr McCall added that the new tax was “really premature”.
“It’s going to rely on the individual, I guess, with what miles they do,” Mr McCall said.
He added there were “more questions than answers” for EV users.
“But we’re already getting questions from members around things like miles in a foreign country – if they drive 2,000 miles across Europe, am I paying for those miles in the UK?”
Mr McCall said it was hard to be exact on the numbers of electric vehicles being driven in Northern Ireland as many are leased to Northern Ireland from companies in Great Britain.
He said his best estimate was “something like 40,000 or 50,00 vehicles with a plug in Northern Ireland”.
“EVs are just 5% of vehicles on the UK’s roads currently,” he said.
“So introducing a pay per mile scheme, even in around two years time, feels really premature to us.”
