Nature-based eco-tourism has helped spark a tourism boom on Kangaroo Island.

Tourism Minister Joan Hall welcomes the latest Bureau of Tourism Research figures which show more than 20 times the international visitors are travelling to Kangaroo Island than in 1985.

Ms Hall says 26,500 overseas tourists toured Kangaroo Island in 1998, compared to 1600 in 1985, making it the South Australian region to experience the biggest increase.

"The world is finally waking up to the island's brilliant position as a naturally pristine holiday spot, with its crystal clear waters offering great conditions for fishing, sailing, whale watching. It's also ideally equipped for cave exploration, four wheel driving and native animal watching," Ms Hall says.

"It also shows our international marketing through the SA Tourism Commission is paying off, as tourists flock to see places like Admiral's Arch and the Little Sahara that they can't see anywhere else in the world.

"Although numbers are up considerably, we still need to encourage visitors to stay on the island instead of just taking day tours.

"To make staying on the island a more attractive option we need to develop more four star accommodation so we can take advantage of the State's fastest growing overseas tourist destination."

In other regions, the Fleurieu Peninsula has experienced a big increase in overnight stays, with more than 30 times more visitors staying in the region overnight, providing a boost for the local economy.