The 1883 Thames St courthouse was closed in late 2011 after being identified as earthquake-prone, which resulted in court services being relocated to the Oamaru Opera House and then to a portable facility known as the ''porta-court'' in Humber St in 2014.
While the exact cost of the work to be carried out by Breen Construction has not been disclosed, Waitaki Mayor Gary Kircher said it was within the $900,000 figure the council had budgeted for the project and would be funded through its endowment fund.
It was expected the work, which will involve metal rods and plates being installed at various points around the building, would start this week and take six months to complete.
After long negotiations, an agreement was reached between the council and the Ministry of Justice in 2016 that resulted in the council taking ownership of the building and leasing it back to the ministry so it could once again serve as the Oamaru District Court.
Mr Kircher said the fact work was about to start was a milestone after several years of frustration.
''It's been a long time coming and there's been a lot of toing and froing between us and the ministry and there's been plenty of challenges along the way. But, both parties have been committed to seeing it through and we are finally there.''
He said those challenges had included reaching a decision on whether the building should be earthquake-strengthened at all and the costs involved.
''It was a challenge from the start when we were facing ranges of around $300,000 to $4million to $6million. There was some serious credibility issues to get past before we could really start talking seriously about it, but we got there.''
Ministry of Justice commercial and property general manager Fraser Gibbs said the ministry was ''delighted'' earthquake-strengthening work was under way.
The technology being used at the temporary courthouse would be installed in the Thames St building.
-By Daniel Birchfield
