Other changes include lane closures on the north west side of the roundabout and a second lane opening on the east side of Tarbock Island.
Full details of the road closures, external are available on the Knowsley Council website.
Tarbock Island is described as one of the region’s busiest transport routes which connects Knowsley to Liverpool city centre and is an access point to the M62, M57 and Knowsley Expressway.
In a statement online the council said the work “will create additional capacity and reduce journey times by increasing the number of lanes on the approaches to the roundabout, as well as widening the roundabout”.
“All possible steps are being taken to minimise disruption but there will be some unavoidable delays to journeys.”
It added: “Drivers are advised to plan ahead, allow extra time for travel, or choose alternative routes where possible.”
The roundabout will be mostly closed to traffic overnight on 9 January for the changes to be made, the council said.