The Ministry of Justice has placed the Business Case for strengthening Dunedin's historic courthouse on its website.

In 2011 the courthouse complex at Stuart Street was assessed as a high risk to occupants in a moderate earthquake. The ministry shifted most of its court services to two leased buildings where they have remained. The leases expire in 2017.

The ministry says the business case - which carries the words "Commercial - In Confidence" - has been released under the Official Information Act. It does not give any further details.

The 41-page report is dated 17 November 2015. It looks at four short list options which were chosen from a "long list" of 11 options.

The options range from strengthening the courthouse to 34% of the National Building Standard, strengthening it to 60-70% (which is the preferred option), extending the leases and selling the building, and extending the leases and deferring remediation.