"In this case, there was a very regrettable communication breakdown which meant they weren't informed about this weekend's road closures on SH4 as early as we would have liked. We will review our processes to make sure this doesn't happen again," Mr l'Anson said.
He said the road needed to be closed because of the scope of the work needed at that particular site.
He said the June storm last year left more than 40 sites along the highway needing repair.
The majority had been repaired but the scale and complexity of the remaining sites, including the one targeted over the weekend, have taken longer to investigate options for repairs.
Mr l'Anson said the work needed to be carried out on the weekend required full road closure, which NZTA recognised caused inconvenience and frustration for road users.
"We'll do all we can to reduce the impact on our customers and will endeavour to open the road up at the end of the day as soon as we can."
He said the repairs would ensure that the highway is stabilised, more resilient and easier to travel on in the future.