Leases for St Bees Island and Long Island Broad Sound off the central Queensland coast are now under state control after being purchased by the Palaszczuk government.

While the purchase prices remain a closely guarded secret, the acquisitions are part of a $262.5 million government plan to expand the state’s protected areas.

St Bees Island’s lease includes 4.2 hectares of land that fronts onto Homestead Bay and consolidates the South Cumberland Islands National Park and the Great Barrier Reef Marine Park.

The once privately owned island contains 70 per cent remnant vegetation habitat for koalas and eastern curlews.

The purchase of the lease and the transfer of 101 hectares will mean the entire St Bees Island will be protected, with the lease area to be rehabilitated.

Long Island is about 20 kilometres long and 5.5 kilometres at its widest point, with salt marshes, mangrove forests, and a range of restricted coastal ecosystems.

The Long Island rolling lease adds an estimated 3500 hectares to the state’s protected areas.

“The purchase of these leases means that unique and critical ecosystems on our Great Barrier Reef will be protected into the future,” Environment Minister Meaghan Scanlon said.

“These areas will now be rehabilitated to support the ongoing management of these islands and better protection for some of our iconic animals.”

While the island leases are not open to the public, plans are under way for both to be rehabilitated and safe to access.

“The entirety of St Bees Island and Long Island Broad Sound will become National Parks, and flatback turtles will be able to lay their clutches on those pristine, isolated beaches,” the minister said.