In a written judgement on the application to file out of time, Chief Judge G L Colgan said the delays were attributable to the "particular and sensitive circumstances'' which were "specific to many residents of Christchurch and not unique to the people involved in this case.''
The lawyer took responsibility for the delays, saying the effects of the February 2011 earthquake and a recently discovered medical condition were to blame.
The tragedy had caused a range of issues, including difficulty with decision-making, and he was receiving counselling from a registered psychologist and other medical treatment.
Judge Colgan found there was no particular prejudice to the intended defendant, Tyco New Zealand Limited, and that medical evidence supplied by Z explained the delays.
"This is a truly extraordinary case in which, but for those circumstances, leave would probably not have been granted.''
The employment case related to David Hugh Wareing, who lost an unfair dismissal case against his former employer Tyco.
Wareing was dismissed after a heated discussion with his team leader, during which he used inappropriate words and left in a fit of anger. After follow-up meetings he was dismissed for serious misconduct.
Wareing had worked for Tyco for 11 years and was nearing retirement.
The authority acknowledged issues of stress arising from the Christchurch earthquake was a factor in his behaviour, but found that he was not unfairly dismissed.
Wareing's new lawyer, Kathryn Dalziel, said the authority did not give enough weight to earthquake stress in its decision, despite the dismissal taking place shortly after the February 2011 quake.
She said there was public interest in a court assessment of the case, which would give guidance on employment matters relating to the earthquake.