The New Zealand Government could be up for another $NZ400 million ($328.44 million) to settle Canterbury earthquake claims it inherited when it took on the earthquake business of AMI in 2011.

When the Christchurch-based mutual came close to collapse the Government pledged $NZ500 million ($410.55 million) in convertible preference shares as a show of strength.

In April last year, when IAG bought the non-earthquake business of AMI, the Government stumped up $NZ100 million ($82.11 million) for the shares, leaving itself with a potential liability for the rest.

Last week John Sweeney, an executive with Southern Response – the name the Government has given to the AMI earthquake claims exposures – said the total likely liability had grown from $NZ254 million ($208.58 million) in November to $NZ400 million ($328.44 million) or more now.

Overall the Government’s earthquake-related costs to date are $NZ11 billion ($9.03 billion), according to recently published government financial statements. The bill will rise further when decisions on replacing regional infrastructure are made.