Brightoil Petroleum Holdings has seen six of its Singapore-based bunker tankers arrested over outstanding debt payments.

The ships have been detained by Singapore law firm Rajah & Tann, but it is unclear at the stage who the law firm is acting for.

The vessels involved are the 7,000-dwt Brightoil 639, Brightoil 688 and the Brightoil 666 as well as the 4,100-dwt Brightoil 319, Brightoil 326 and Brightoil 329.

Meanwhile, creditors of Brightoil Singapore have filed two lawsuits and an order to liquidate the company in Singapore’s High Court.

Vietnam’s top fuel importer Petrolimex filed an application for a winding up order for the company after it failed to meet deadlines to repay more than $30m in outstanding debt, according to a court hearing on Friday, reported Reuters.

Brightoil reportedly had a settlement agreement in July in which it agreed to repay the debt to Petrolimex in four installments.

The hearing has been adjourned to 14 December to provide the holding company of Brightoil more time to work on its debt restructuring efforts, according to the court hearing.

In a separate case to be heard on Wednesday, Qatar National Bank (QNB) has made a claim against Brightoil Singapore and its holding company for $21.6m.

QNB paid four letters of credit on behalf of Brightoil between March and May. QNB also provided short-term advances to Brightoil which were due in June and July, reported Reuters.

Hong Kong-based Sea Trader International is also suing Brightoil’s Singapore arm for nearly $1m for the sale of goods, court documents showed.