The Abrolhos Islands off Western Australia's Mid-West coast are set to become the state's newest national park.

The islands comprise a group of more than 120 coral cays that lie scattered across 100 kilometres of the Indian Ocean west of Geraldton.

Premier Colin Barnett announced the move at the Liberal party state conference in Perth today, describing the Abrolhos as "the jewel in the crown of the Mid-West coast."

The area is home to the wreck of the ship Batavia, which was carrying gold, silver and 180 people when it went off course in the Abrolhos in 1629.

But the park does not include waters around the island, instead focusing on the land component of about 90 per cent of the islands.

This means recreational and commercial fishers will not be affected by the plans.

About 21 of the islands currently house some infrastructure including fishermen's shacks, private jetties and Department of Fisheries infrastructure.

The national park will cover the unoccupied islands and will be managed by the Department of Parks and Wildlife.

"The Abrolhos are the jewel in the crown of the Mid-West coast, but have been largely untapped for tourism purposes," Mr Barnett said.

"This new arrangement will ensure better access and also lead to better visitor facilities on the islands."

The Premier said the tourism potential of the islands was vast and the port city of Geraldton would also reap rewards, as it was an ideal base for visitors to the Abrolhos.