He said the train will begin training on the tracks in Hamilton this week up until the launch date.
"The delay of the service is likely because of a new issue that has surfaced. What has come up is the concern about fatigue of some of the tracks in the Auckland area. There is about 2km of tracks that require some engineering.
"KiwiRail has identified some concerns that they need to work on and what that means is that they will have to introduce some speed restrictions for a period of time."
Wilson said council had been concerned over a lack of demand of the service during the summer months when the maintenance would be taking place, due to fewer workers heading into the city.
"We are also mindful in light of the latest Covid cluster in Auckland, and the perception of public transport right now, then it seems we are best to delay the service once Covid issues have been resolved and the engineering that needed to be done is completed."
Rail governance working group chairman Hugh Vercoe told Radio New Zealand while the delay was extremely disappointing, the safety issue with the track could not be ignored.
He said running the service while the maintenance work was being done would mean speed restrictions adding another half an hour to the 140-minute trip.
Vercoe said it was better to delay the start now rather than be faced with the track maintenance issue once the service was under way.
"It is disappointing but we have to get it right."
A delay to the completion of a new transport hub at Rotokauri on the northern outskirts of Hamilton has been caused by Covid-19 level 3 restrictions in Auckland stopping some tradespeople from coming down from Auckland.
Vercoe said delays to getting the commuter service, which will involve two return trips each day between the two cities, were frustrating but he was confident it would prove successful.
"It is going to happen, it will happen."
Vercoe said a February starting date was likely. He said the message to KiwiRail was clear.
"Don't give us a date and hope you can make it because that makes us all look stupid. Give us a date that you can say 'we guarantee the tracks will be safe, everything will be ready to go on this date'."