Has the Turnbull government unwittingly sealed its own fate at the next election by encouraging young people to register on the electoral roll to participate in the postal plebiscite on same-sex marriage?

Former Liberal leader John Hewson believes it could prove counterproductive at the next federal election.

The Australian Electoral Commission said last week there had been a surge in "electoral transactions", recording 68,000 on one day alone when a daily average would average 4000.

Dr Hewson described it as the "Theresa May affect", the British prime minister who was expected to win the recent UK election by a landslide but ended up with a minority government because of an unusual amount of young people voting and backing Labour.