The Australian Electoral Commission determines the number of seats for every state and territory one year after the first sitting for a new House of Representatives.

The AEC reported on Thursday that, based on population changes, South Australia would lose one seat, taking its MPs to 10, and Victoria and the ACT would gain one seat each – taking the total number of lower house electorates to 151.

The number of federal seats in Victoria would go from 37 to 38 and the ACT would have three.

Electoral commissioner Tom Rogers said redistributions for Victoria, SA and the ACT would start soon.

“Redistribution committees will be appointed and the public will soon be invited to make suggestions and comments on matters affecting the drawing of federal electoral boundaries and the naming of electoral divisions,” he said.

Redistributions are already under way in Queensland and Tasmania, but the number of seats there won’t change.

If a federal election is called before the SA redistribution, it is expected the Liberal-held seats of Grey and Barker will be merged to form an area covering 98 per cent of the state’s landmass.

Election analyst Antony Green told the ABC if the SA redistribution was completed, one seat in Adelaide – likely to be a Liberal-held electorate – would disappear and the rest of the state would adjust around it.

The new Victorian seat, expected in Melbourne’s northwest, would likely go to Labor.

The ACT’s new seat could go to Labor but the Liberals have been making gains in territory elections in recent years.

The Queensland redistribution is expected to take 14 months to complete, concluding in March next year.

There has been speculation Prime Minister Malcolm Turnbull might head to the polls in late 2018, before the SA, ACT and Victorian redistributions are finalised.

– AAP