Seven people are dead and several others missing after a ferry sank off Indonesia's Sulawesi island.

The public ferry was about 24 kilometres from the town of Kolaka in south-east Sulawesi when it ran into bad weather.

Officials say search and rescue teams were able to rescue 95 people.

Another five are believed missing, but the total number of passengers on the ferry is yet to be confirmed.

"We have found 61 adults, 13 children and 19 crew members who are still alive," said a port official, Zainuddin.

"The rescue team is still searching for several more people. We suspect some people are still missing as the passenger list of the ferry is inaccurate."

Sea accidents are common in the archipelago and safety standards are often overlooked.