Lismore motorists heading north over the next few days are advised of changed traffic conditions on the Pacific Motorway at Chinderah.

The work from tonight until Thursday, is to carry out overnight investigations for options to reduce traffic noise from Barneys Point Bridge.

To reduce impact to motorists, two of the three northbound lanes will be closed from 7pm on Tuesday 8 December to 5am on Wednesday 9 December and two of the three southbound lanes will be closed from 7pm on Wednesday 9 December to 5am on Thursday 10 December.

Work involves testing the depth of asphalt at various locations on the bridge as part of measures to reduce noise and provide motorists with a smoother ride.

Traffic control and a reduced speed limit of 40km/h will be in place for the safety of workers and motorists. There will also be occasional closures of up to five minutes of all southbound or northbound lanes, which may impact travel times.

Motorists are advised to drive to the conditions, and follow the directions of signs and traffic control.

Transport for NSW thanks motorists for their patience during this time.

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