Bridge strengthening work is to begin on Paytens Bridge next Monday 5 May.

Transport for NSW has advised of changed traffic conditions on the bridge, on Paytens Bridge Road 11 kilometres south-west of Eugowra for an expected four months.

Work will include installing scaffolding under the bridge and assembling a strengthening structure called a Bailey bridge which will then be craned onto the bridge deck.

Work will be carried out between 7am and 6pm from Monday to Friday and is expected to take four months to complete, weather permitting.

Until the work is finished, the existing 23-tonne load limit on Paytens Bridge will remain in place along with a reduced speed limit of 10 km/h on the bridge and barriers to direct traffic to the upstream side of the bridge.

Temporary traffic changes will also be in place within the work area including intermittent stopping, single lane closures and a reduced speed limit of 40 km/h through the work area during work hours.

The speed limit within the work zone will return to 100 km/h outside of work hours, except on the bridge which will remain at 10 km/h.

Motorists in vehicles under 23 tonnes using Paytens Bridge Road are advised to allow 10 minutes of extra travel time.

Vehicles over 23 tonnes travelling between Eugowra and Lachlan Valley Way need to detour via Casuarina Drive to Gooloogong - they will not be able to use Paytens Bridge Road.

Motorists using the detour are advised to allow 30 minutes of extra travel time.

Transport for NSW thanks motorists for their patience and reminds them to follow the directions of traffic controllers and signs.

For the latest traffic updates, you can download the Live Traffic NSW app, visit livetraffic.com or call 132 701.