Repairs to a bridge on the Desert Road damaged in a truck crash last July are expected to continue to impact State Highway 1 traffic in the central North Island for the next two months.

Vehicles with over-weight loads or over-dimension loads wider than 3.0 metres will not be able to use the Desert Road section of SH1 for the next few months as it will not be possible to cross the damaged Waihohonu Stream Bridge.

Other traffic is being restricted to one lane over the bridge, with a 30km/h speed limit and occasional mini-closures of around five minutes.

Two full closures of the highway to all traffic are scheduled (for March 7 and April 4, but subject to change according to the weather) to allow for the pouring of a new concrete bridge deck.

Each closure is expected to be from 7am for around 36 hours. The recommended alternative route during the closures is via SH46, SH47, SH4 and SH49 – through National Park, Ohakune and Waiouru. It could add around 40 minutes to a journey.

NZTA says this route is not suitable for vehicles over 44 tonnes, "apart from 50MAX, which is permitted. High productivity motor vehicles can use the SH3 and SH3A route between Hamilton and Bulls (via Taranaki)."

There will also be multiple maintenance work sites on the Desert Road during this period and there are delays possible at other sites.

NZTA Waikato transport system manager Karen Boyt says people using the Desert Road should expect some delays and should check before they travel – either on the Agency website or by phoning 0800 4 HIGHWAYS.