MD Construction had accepted a complaint from another employee that Collier pulled her ear after he was made to wait for a fuel card.
The complainant said he reached out and twisted her ear "similar to what someone would do to a naughty child".
While accepting his hand made contact with his co-worker's ear, Collier said it was unintentional. He said she moved slightly and his hand had "flicked" her ear.
Around the time he was made aware of the complaint, Collier learned there was a recording of him joking about relaxed work hours while talking to a man on the side of the road.
He had been finishing paperwork in his work van near the Ngauranga interchange when he was filmed by the unknown man who had asked him about potential work.
A disciplinary process followed with a focus on Collier's time management and the ear-pulling allegation.
Collier denied the accusation and argued the video was a set-up and that his comments in it were made in jest.
But he was fired from his role without notice on the grounds of assaulting another employee, failing to work his required hours and inaccurate time recording.
The company told Collier his conduct "was unacceptable and disregarded company values".
Collier, who started work for MD Construction in 2018 doing maintenance work on houses for the company in Wellington, felt humiliated.
He turned to the ERA, claiming his dismissal was unjustified.
Collier told the authority that the way the allegations had been handled had caused both himself and his family great distress.
He had found it difficult to find employment because of the nature of his dismissal, and after door-knocking for months found a new job in January last year.
But MD Construction told the authority they had investigated Collier's alleged misconduct and that its process was fair.
The ERA has ruled, however, that the investigation was insufficient and the use of the anonymous video was in breach of the employer's good faith obligations.
"Mr Collier's explanations were not given genuine consideration and that in these circumstances a fair and reasonable employer could not have reached the conclusion that Mr Collier had committed serious misconduct," the decision stated.
"There were also significant defects in the process that were not minor and have resulted in unfairness to Mr Collier."
The authority was satisfied the "covert video recording", of which the origins are unknown, was either obtained unlawfully for the purposes of an employment investigation, because an employment investigator recorded the video, or to have provided insufficient information about Collier's conduct for MD Construction to have reached the conclusions it did.
"I am satisfied it was not open to MD Construction to conclude that allegation was proven based only on the information from the video," the decision said.
