Norwegian yards are faring fairly well after the disastrous fall in the oil and gas industry. (See my post in Shipyard News thread today)
From building almost exclusively for the Offshore Oil & Gas sector, they have diversified into for the Offshore Wind farm industry, Aquaculture, Ferries and Expedition Cruise vessels.
Most Norwegians don’t give a toss about the shipbuilding and marine equipment industry, since it is concentrated in a relatively small part along the west coast and most people live in the east, around the Oslo area.
But to answer your question from the west coast; It would make no sense to build the hulls in Norway, with the most expensive labour force in the world. To import foreign labourers to do so in Norway would also be uneconomical, since Norwegian laws demand that they be paid Norwegian wages and get Norwegian benefits.
Welding steel together into an empty shell only represent abt. 30% of the cost of the completed vessel when we are talking about complex vessels of the type that is built here. The machinery and equipment cost answer for 40-45% and the design and outfitting costs for the rest.
BTW; Much of the work force at the shipyards are foreign contract labour, since there is a shortage of such workers in Norway.
Since Norwegian shipyards don’t have a captive market, but must be competitive on the world market, even for ships built for Norwegian owners and coastal trade, they cannot afford to spend money on the simpler tasks, like hull building, which is contracted out to yards with lower labour cost. Some hulls are built at yards owned and managed by the yards in Norway (Vard), others build sections abroad and weld them together in Norway.
Some of the smaller yards building service boats for the aquaculture industry and small fishing vessels etc. and those building fast ferries from aluminium or composite material build the hulls in Norway.