The Nationals backbencher wants to split each state into six regions - like mega electorates - that each vote for two senators.

He points to the current situation where 11 out of the 12 senators in Victoria, Western Australia and South Australia have offices based in their state's capital.

"That's ridiculous," Mr Joyce told reporters in Canberra on Monday.

"If New York can live with two senators and they do a very good job, why does Adelaide need 11?"

He believes the Senate's role is to deal with the nation's geographic diversity while the lower house represents demographic intensity, with each member having constituencies of roughly the same number of people.

Mr Joyce will ask the Nationals federal council to back his plan on Saturday.

Under his proposal, no region could be bigger than 30 per cent of the state's landmass and the capital city would be confined to a single region.

Only three of the regions in each state would vote in each half-Senate election, providing the six senators for each term.

That would mean people living in half the state would miss out on getting a say in the upper house.

Election expert Kevin Bonham has questioned the constitutionality of the idea.

Mr Joyce argues that at the moment, the areas outside the capital cities effectively aren't represented, despite the fact that constitutionally senators represent their whole state.

"What it would mean is that senator would actually have to represent a constituency of people in a very real way or they just wouldn't get elected."

Greens leader Richard Di Natale - who lives in regional Victoria, although his office is in Melbourne - said it would be a great thing to have more representation from outside the major cities.

"If Barnaby Joyce wants to have a conversation about what a representative parliament looks like, then he'll be joining us in advocating for proportional representation," he told reporters.

"The Greens get double the National Party vote, we get one member of the lower house; the National Party, they get half of our vote, what have they got, I think it's 16 MPs in the lower house."

Mr Joyce's Nationals colleague Matt Canavan has offered a different proposal to formalise the "patron" arrangements major parties have to assign senators to look after particular lower house seats.

Under his plan, senators for each state would nominate which region they wanted to represent and the upper house would then allocate them.

Senators would report annually on how they had represented their patron area but Mr Joyce is sceptical that would work.

Australian Associated Press