Mr Cull and Auckland Mayor Len Brown last week released a joint letter arguing against aspects of the Building (Earthquake-Prone Buildings) Amendment Bill, which is before a government select committee.
The Bill would give councils five years to assess nearly 200,000 buildings - including all non-residential and high-rise, multi-unit apartment buildings - for earthquake risks.
Owners of earthquake-prone buildings would then get another 15 years to upgrade to at least 34% of building code requirements.
The Dunedin City Council has already warned it would face a $5.6 million bill if forced to assess about 4200 buildings, and some building owners could abandon heritage properties rather than pay for upgrades.
In Auckland, the total cost of upgrading buildings could top $3 billion, despite modelling showing there would be no significant safety improvement in the seismically low-risk Super City, the New Zealand Herald reported earlier this month.
Mr Cull yesterday told the Otago Daily Times the joint approach underscored that concerns prompted by the Bill were shared across New Zealand.
While the two cities' specific concerns were different, each faced significant costs that were ''way out of proportion to the risks'' as a result of the ''clumsy, one-size-fits-all legislation'', he said.
''This is applying an extremely blunt instrument to everybody, regardless of the risk and regardless of the benefits. In their case, it'll cost them a lot of money. In our case, it could cost us a lot of buildings.
''I think it really raises the question about whether any council is going to be advantaged by this,'' he said.
Mr Brown, in a statement, said the two councils had identified ''common issues which we believe need serious consideration''.
''It is clear that further work is needed and we encourage select committee members to act on these submissions before the Bill is passed into law.''
The pair's letter followed earlier submissions by councils including the DCC and a joint Southern Councils submission.
Mr Cull said he expected to present the DCC's submission to the select committee later this year.
