Malaysia said Thursday it believes 139 people are buried in graves at remote detention camps used by people-smugglers on the Thai border which were discovered on the weekend.

"Based on the size of the graves, and after the area was cleared... we have a clearer indication -- single grave, single person," Deputy Home Minister Wan Junaidi Tuanku Jaafar told reporters.

When asked by AFP if he believed that there are 139 bodies since Malaysia has previously said it had discovered 139 grave sites, Wan Junaidi said: "Yes".