During the Great Depression the department was relied on by the government to provide unemployment relief, constructing infrastructure mostly using human labour at reduced salaries.

This was to reflect the extended wartime functions, when the Minister explained it was, "to ensure that, whilst the building and constructional potential of the country is limited by war and immediate post-war conditions, it is assembled and utilized in the most efficient manner from the point of view of the national interest".

The list of items to be shipped from New Zealand to Moscow (via Tehran and Central Asia) included 40 armchairs, 10 couches, a billiard table, and palm stands.

The primary purpose of this 6000 strong workforce was the maintenance of the existing and planning and construction of replacement sections of the State Highway network.

While the policy functions were either disestablished or passed on to other Government departments, the commercial operations were set up as Works and Development Services Corporation (a state-owned enterprise) and the computing bureau and the buildings maintenance units were sold.

This branch was not solely used to service the dam project; the PWD used its own rolling stock to provide a service for school children who attended school in Kurow, and occasionally special Railways Department trains operated on the line with PWD motive power, including a 1931 sightseeing excursion to view the under-construction dam.