A crane will be needed to help install a temporary fix on a weak pile in Whangārei's Town Basin.
Whangārei District Council parks and recreation manager Sue Hodge said the failing pile was discovered last week.
She said the council had the pile inspected by engineers.
The engineers recommended restricting public access and carrying out a temporary fix until a permanent solution is implemented.
The pile is underneath the cantilevered deck near the marina office. Fences have been put up to restrict public access to the affected section of deck and the gangway has been limited to one person at a time.
Hodge said the pile had weakness in it but it was not clear what caused it.
The pile looked to be on an angle when the Northern Advocate visited the site.
A crane will be used to temporarily support the marina veranda deck so the pile can be worked on.
The pile will be removed down to where the wood is sound then a steel sleeve will go over the lower portion of remaining wood.
A new timber pile will be slotted into the sleeve on top of the remaining pile.
A crane will then jack up the deck to level.
It will be a temporary fix until a permanent one is designed and installed.
Hodge said work was expected to start within the next week. The cost is not yet known.