The four-month closure of two slip roads between the M2 and the A249 has been extended just days after National Highways confirmed the weather had not affected its reopening.
Due to the recent cold weather the motorway maintenance company said it was unable to complete the final surfacing and white lining as originally planned.
The slip roads will now open on Monday, January 23, 10 days later than initially promised.
Last week National Highways confirmed there would be no delay as a result of the recent spell of snow, with the busy route returning to normal on January 13.
But today a spokesman said the slip roads will remain closed for longer than they initially thought.
A statement read: "We’re making good progress with the construction of the new coastbound slip roads.
"Unfortunately, due to the recent weather, we’ve been unable to complete the final surfacing and white lining as originally planned.
"This means that we need to keep the slip roads closed for a little longer than we thought.
"We’re now planning to reopen the slip roads by Monday, January 23, subject to weather conditions.
"We continue to work with the local authorities and emergency services while these, and any closures linked to the scheme, are in place."
The extension comes as several other closures in the new year have been announced.
The A249 Sheppey-bound between the Stockbury roundabout and Bobbing will be a fully closed from 8pm Friday nights until 5am Monday mornings across the weekends of January 13, 20 and 27, February 3, 10, 17 and 24, and finally March 3.
There will be a lane closure at the same time as the closure on the A249 Sheppey-bound on the A249 Maidstone-bound between Bobbing and the Stockbury roundabout, with one lane remaining open.
For drivers heading towards Sheppey from the Stockbury roundabout, there will be a diversion in place via Maidstone Road, Chestnut Street, and Sheppey Way.
National Highways has been finishing the widening work on the new £92m Stockbury flyover linking the A249 with the M2 at junction 5.
A spokesman for National Highways said: "We appreciate that these roadworks may cause delays and disruption, and are grateful for people’s patience while we deliver this important upgrade at junction 5 on the M2.
"Any delays due to weather have not affected the end date of the project which is still on track."