The company said some costs within the Oil & Gas business area had not been accounted for in its financial reports between 1998 and 2000.
The costs could not be allocated to each individual accounting period and impact directly on the Oil & Gas sector in the 1998-2000 accounts.
It added: ‘The costs relate to the delayed recording of labour hours and negative variances between budgeted and actual hourly rates.
‘The Group expects these costs to have a minor negative impact on the result for the Oil & Gas business area in 2001.’
According to Kvaerner, the costs will not affect liquidity and it had made provisions for the period in question, of which NOK 200m (£16m) had not yet been used.
Last year Kvaerner narrowly escaped bankruptcy.
Mark McMullen joins the private client services team from Smith & Williamson
Merger between Clear & Lane Chartered Accountants and Magma Chartered Accountants was finalised on 3 February
BDO has taken its new partner intake to 23 during the first half of its financial year, including the appointment of five partners in five weeks
The firm reports 7.6% global fee income growth for the year ending 31 December 2016