Like all original states, Tasmania has a constitutional right to at least five House of Representative electorates regardless of its population, unlike the territories.

NT lost its second seat while Victoria gained one based on population, causing political concern among territory MPs who have urged the Morrison Government to support a private members bill to retain their two lower house electorates.

The change means the NT would have one lower house seat for 140,000 electors, while Tasmania's five electorates - Bass, Braddon, Clark, Franklin and Lyons - have an average of 77,500 electors, according to the latest data from the Australian Electoral Commission.

Almost all mainland electorates have at least 100,000 electors, apart from two each in the ACT and Western Australia which are in the mid-to-high 90,000s.

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University of Tasmania senior lecturer in law Brendan Gogarty said the constitution was designed to ensure smaller states like Tasmania were guaranteed a strong voice in Parliament.

He said changing this would require a double majority referendum that was destined to fail, whereas granting the territories full representation was at the will of the Parliament.

"I understand that some have described Tasmania's position as overrepresentation. I do not share that view, and it belies a misunderstanding of the federation and constitutional arrangements," Dr Gogarty said.

"Proportional representation is central to our constitutional system and is given primacy, but our constitution also recognises the distorting and problematic nature of a system that is entirely based on population density to determine national policy.

"The Senate was designed to be the state's house, and while this role may sometimes be considered vestigial, it remains a powerful and important limit on majoritarianism and political parochialism and favouritism which would result from one-vote-one-value being the sole framework for federal representation."