Two of the Furneaux Group's 78 Islands are up for grabs in a rare double-changeover of long-term tenants.

The Crown leaseholds of Prime Seal and Passage islands are listed for sale with Roberts Flinders Island, while a 17-hectare private leasehold on Little Dog Island near Lady Barron has also attracted interest.

Roberts agent Colin Wilson said it was unusual to have one island available, let alone two at once.

"Both [Prime Seal and Passage Island] have been long-held leases, being controlled by their respective managers for 30 years or so I think," Mr Wilson said.

"They're both ideal for farming, but it's everyone's dream I think, to have an island and enjoy the isolation and beauty."

The 1220-hectare Prime Seal Island, where Labor leader Bryan Green survived a light plane crash in 2006, has 16 years remaining on its 20-year renewable grazing lease, with livestock, plant machinery and living quarters included in the deal.

Mr Wilson said the Prime Seal lease had attracted interest "from near and far" - but he was not willing to disclose the price range of bids.

Meanwhile, the 242-hectare Passage Island lease is available for $175,000, with two airstrips and a licence to carry up to 32 cattle.

The Little Dog Island parcel includes two beaches and two cedar shacks, and is expected to go for more than $200,000.

Tasmanian Aboriginal Land Council chairman Clyde Mansell said the islands, like many in the Furneaux group, had important indigenous value.

But Mr Mansell said the TALC was unlikely to make a bid for any of the current leases.

"We are open to negotiations with the state government should the leases ever expire," Mr Mansell said.

"We believe that there needs to be a recognition that these lands were taken from our community, instead of us having to buy the back."

Other notable Tasmanian islands sold in recent years include Smooth Island and King George Island, both off the Forestier Peninsula, for about $900,000 and $500,000 respectively.

Businessman Gunter Jaeger also built a private castle on the isthmus Boomer Island in Blackman Bay, while Picnic Island off the Freycinet Peninsula was at one point also listed for sale.