Insurers’ victory against Christchurch City Council over the imposition of stricter building-strengthening rules is to be tested in New Zealand’s highest court.

Last year the Insurance Council of New Zealand won a High Court case that stopped the council requiring building owners to strengthen to 67% of new building code requirements, up from 34%.

The ruling could have cost insurers millions of dollars in upgrade bills.

The council did not argue that decision, but the University of Canterbury and another building owner challenged it in the Court of Appeal, which upheld the original ruling.

Last week the university – which owns a number of historic buildings – won the right to appeal to the Supreme Court, which will rule on the council’s power to impose tighter regulations.