The nation's big three shipbuilders have all posted a surplus in the first quarter.

As new orders have also improved this year, observers point to signs of a budding revival of the shipbuilding sector that has been fighting a severe recession.

According to industry sources on Friday, Hyundai Heavy Industries' operating profit surged 90 percent year-on-year to reach nearly 619 billion won from January to March, continuing a surplus streak for the fifth straight quarter.

The troubled shipyard Daewoo Shipbuilding and Marine Engineering, which ran a deficit since 2013, also swung to the black for the first time in 17 quarters. It posted an operating income of close to 300 billion won in the first quarter.

Samsung Heavy Industries also logged an operating profit of 27-point-five billion won to continue a surplus for the third quarter.