Coasties, be prepared for a nighttime detour next Monday.

NZ Transport Agency (NZTA) has announced a full closure of State Highway 1 between Silverdale and Warkworth from 9 pm on Monday, 21 October, to 5 am on Tuesday, 22 October.

The closure, weather dependent, will allow Waka Kotahi to team up with Fire and Emergency NZ (FENZ) and NZ Police for an emergency exercise within the Johnstones Hill Tunnel.

This training is part of ongoing programmes across Auckland's major tunnels, including Waterview and Victoria Park.

Light vehicles will be rerouted via Hibiscus Coast Road and Old State Highway 1.

However, overweight vehicles won't be able to use Grand Drive in Orewa due to weight restrictions.

According to NZTA, these exercises enable emergency teams to rehearse, review, and update response protocols.

Remember to reduce speed, follow temporary limits, and adhere to traffic management directions when navigating work sites.