The Canterbury Earthquakes Royal Commission has recommended that unreinforced masonry buildings around New Zealand be improved as soon as practicable.

The royal commission’s interim report says local authorities nationwide should keep registers on unreinforced masonry buildings, which should be strengthened by bracing parapets, installing roof ties and securing external falling hazards near public spaces.

The inquiry into building failure in the earthquakes estimates New Zealand has 3500 unreinforced masonry buildings and says 42 people died in Christchurch when such buildings collapsed or partially collapsed.

But a report to the royal commission last month said it would cost $NZ2 billion ($1.56 billion) to upgrade all the buildings, and they are only worth $NZ3.5 billion ($2.7 billion).

The report identifies public safety implications for all New Zealand’s multi-storey buildings, and says changes to construction and design standards should be addressed immediately.

It recommends designers consider new building technologies and recommends urgent work to update design standards.

It also says Christchurch City Council should require thorough soils investigations prior to foundation design.

The royal commission’s work so far has involved commissioning and receiving technical reports on seismicity, soils and buildings.

Its final report to be completed by April 11 next year will address the failings of the Pyne Gould and Canterbury Television buildings.

Building and Construction Minister Maurice Williamson says his department is already working on aspects of the recommendations, with a specialist team looking at design standards, new technologies and stair design.