RIG builder Sembcorp Marine posted a modest rise in first-quarter earnings thanks mainly to brighter operating margins from key operations.

Net profit for the three months to March 31 increased 5 per cent from the same period last year to $119 million.

Turnover grew 11 per cent to $1.1 billion, due largely to higher revenue recognition from rig building.

SembMarine said two core businesses expanded in the first quarter.

The rig building sector posted the strongest growth, with revenue surging 52 per cent from $393 million a year ago to $598 million.

Its ship repair business was also in expansion mode, registering turnover growth of 9 per cent from $143 million to $156 million.

Earnings per share rose to 5.69 cents from 5.43 cents previously while net asset value per share firmed to 121.65 cents compared with 116.80 cents as at Dec 31.

SembMarine has a net cash position of $1.2 billion and a record net order book of $13.6 billion, with completion and deliveries stretching until 2019.

This includes $1.7 billion in rig orders and offshore platform contracts secured since the start of 2013.

SembMarine shares closed two cents down at $4.26. The results were announced after markets had closed.