Already accused of bribery, three former senior executives of ship builder ST Marine were yesterday hauled back to court to face nearly 1,700 fresh charges of conspiring to make false claims for non-existent entertainment expenses involving millions of dollars.

Former senior vice-president Mok Kim Whang, 65, former president of commercial business Tan Mong Seng, 64, and former executive vice-president Han Yew Kwang, 58, were allegedly involved in a plot to abuse the firm's petty cash voucher system between 2000 and 2009.

Mok, senior vice-president from June 2000 to July 2004, was charged in end-2014 with conspiring to give a nearly $44,000 bribe to a Hyundai Engineering and Construction employee, between 2004 and 2010.

He now faces 824 new charges of conspiring to make false entries for fake entertainment expenses worth $3.13 million between 2000 and 2004. For instance, he is accused of approving reimbursement claims for entertainment expenses never incurred. He is also accused of two counts of submitting fake claims worth $5,000, bringing his total number of new charges to 826.

Tan and Han were first charged last July. The former was accused of conspiring to give a $43,721 bribe to the Hyundai employee, while Han faced eight counts of scheming to give $790,772 in bribes, in return for favours such as ship repair contracts, to agents of ST Marine's customers between 2004 and 2009.

Tan left the company in June 2002, and Han, in June 2014.

Tan now faces 445 charges of conspiring to make false entries for $1.64 million in fake entertainment claims between 2002 and 2004, while Han faces 473 charges involving $1.86 million for claims between 2004 and 2009.

The trio, who are out on bail of $200,000, are among seven former ST Marine senior executives who have been charged for graft or falsification of accounts. They include former ST Marine presidents See Leong Teck and Chang Cheow Teck.

See, who was president from December 1997 to February 2008, was succeeded by Chang, who held the role until April 2010 before moving to ST Aerospace. See is accused of seven counts of conspiring to corruptly bribe agents of the shipyard's customers, while Chang is accused of giving almost $274,000 in bribes on three occasions.

The firm's former group financial controller Patrick Lee Swee Ching, 58, pleaded guilty to falsifying documents to cover up corrupt payments worth over $126,000, and was fined $210,000 last July. He escaped a jail term as he had, among other things, committed to testify against his alleged co-conspirators.

ST Marine is a unit of publicly listed ST Engineering, which yesterday told the local stock exchange that its subsidiary has cooperated fully with the Corrupt Practices Investigation Bureau since investigations began in 2011. The new charges are unlikely to have "any material impact" on its bottom line, it said, and it is "committed to maintaining high standards of corporate governance".