The sole proprietor of a manufacturing firm found guilty of evading income tax and goods and services (GST) tax has been sentenced to six months' jail and ordered to pay nearly $1 million in penalties.

Eddie Choy Hon Cheong, 59, was convicted in court last Friday for wilfully evading tax, having made false entries in his GST and income tax returns between the accounting periods 2010 and 2012.

Court documents show that the boss of Cubitt Engineering, which manufactures oil and gas equipment, had underpaid taxes amounting to $455,692.51. He has since repaid the Inland Revenue Authority of Singapore (Iras) the outstanding amount in full.

He was then made to pay further financial penalties amounting to $996,236.

Choy faced 30 charges relating to tax evasion and making false entries, court documents show. He not only falsely inflated his company's expenses but also omitted sales made to two other companies, offences under the Income Tax Act and the Goods and Services Tax Act.

For instance, he stated that the GST tax due for the accounting period ending Dec 31, 2010 was $39,427.64 when the actual amount due was $42,529.02.

For the accounting period ending March 31, 2011, he also stated he owed Iras $26,710.48 when in fact he should have paid $30,874.75.