The executive board of PT Garuda Indonesia's workers union went to the Corruption Eradication Commission (KPK) to file a report on indications of graft within the company.

"We have brought proof of suspicious transactions since 2006," union spokesman Tomy Tampatty said on Wednesday, as quoted by tribunnews.com.

Tomy added that the union had previously sent four documents and other data related to the graft indications to the KPK from 2006 to 2010, but he said that no follow up examination had been made up to this date.

All four letters, he said, each contained reports of distinct corruption allegations. According to the union's estimates, the graft allegations could amount to around Rp 140 billion (US$15.68 million) of losses to the state.