Investigators looking into the sale of two oil tankers by Indonesia's state-owned oil company Pertamina, which resulted in a claimed $50 million loss for the country, are to visit Bermuda to speak with company bosses of Frontline Shipping.

Their visit will be part of a worldwide investigation that will also include carrying out inquiries at South Korea's Hyundai Heavy Industry, Goldman Sachs in the US and partially Indonesia-owned Equinox Sailing.

Bermuda's Frontline Shipping bought two tankers for $184m while they were under construction at Hyundai in South Korea, but the sale was allegedly not endorsed by Indonesia's finance minister.

The Attorney General's Office in Indonesia announced the wide-reaching investigation on Tuesday, according to a report in The Jakarta Post, newspaper.

A team of Indonesian prosecutors will travel to question companies allegedly involved in the sale after three of the four ignored a summons from the AGO, said the newspaper, which stated that Equinox Sailing was the only one of the companies to send a representative for questioning.

The schedule for the prosecution team's visit to Bermuda, the US and South Korea, has not been finalised. The team is to be headed by prosecutor Slamet Wahyudi.

According to the Jakarta Post report: "Pertamina sold two of its tankers for $184 million while they were still under construction at Hyundai in South Korea. The tender-winner was Bermuda-based Frontline Shipping Ltd.

"AGO investigators found the sale had been made without endorsement from Indonesia's finance minister. The sale price was allegedly below the standard price for this type of tanker, which ranges between $204 million and $240 million each."

Hyundai built the tankers, Frontline bought them, Goldman Sachs acted as a financial consultant for the sale and Equinox Sailing as a mediator. for Frontline.

Criminal law expert from the University of Indonesia, Indriyanto Seno Aji said the AGO should conduct the investigation with legal assistance and cooperation from the countries involved.

The Jakarta Post newspaper said: "Indonesia's Corruption Eradication Commission started its investigation into the alleged graft case in 2004, but could find no proof the tanker sales had inflicted state losses. The AGO has continued to pursue the case regardless."