JAKARTA - INDONESIA has grounded five airlines and given them three months to improve safety standards or face a ban, a transport ministry spokesman said on Tuesday.

A safety audit found airlines Helizona, SMAC, Asco Nusa Air, Tri-MG Intra Asia Airlines and Dirgantara Air Service failed to meet minimum standards in all safety categories, spokesman Bambang Ervan said.

The airlines have been moved into the transport ministry's bottom safety ranking and have had their Air Operator's Certificates (AOC) suspended, Mr Ervan said.

'They can't fly because their certificates have been frozen. If after three months they don't take any action, their AOCs will be revoked,' he said.

The transport ministry in June revoked the AOC of Adam Air after the troubled budget carrier failed to meet a three-month deadline to improve its safety standards.

Indonesia, which relies on air routes to link its thousands of islands, has one of the world's worst air safety records. -- AFP