The long-awaited NorthConnex - twin nine-kilometre tunnels that will reduce traffic on Pennant Hills Road, the congested connection from the Sydney end of the M1 to the M2 - is set to open in a matter of months.

Upgrades to the M1 Motorway between Doyalson and Tuggerah, and Kariong and Somersby, are also nearing completion and are expected to be finished within the next few months.

The two projects, part of $400 million worth of works which included the Weakleys Drive and John Renshaw Drive intersection upgrade at Beresfield that was completed last year, have progressed over the past three years.

The 12-kilometre stretch between Doyalson and Tuggerah has been widened to three lanes in each direction.

The Warnervale and Doyalson interchanges have also been upgraded, and the bridges at Sparks Road and St Johns Road widened.

Further south, the motorway has been widened to three lanes in each direction between Kariong and Somersby to cater for increased traffic flows.

The works also involved lengthening and widening three of the four ramps at the Kariong interchange.

The completion of the projects comes at a time when many commuters are expected to steer clear of public transport due to social-distancing measures.

Before the pandemic, more than 70,000 light and heavy vehicles travelled between the Hunter, Central Coast and Sydney each day. Between the M1 and passenger rail services, tens of thousands of workers also usually commute between the Central Coast and Sydney each day

The $3 billion NorthConnex, initially slated to open late last year but now almost ready, will free up - and allow motorists to avoid - one of the most despised sections of Sydney's road network.

By using the new toll road, motorists will avoid 21 sets of traffic lights on Pennant Hills Road and save up to 15 minutes in travel time.

The link will allow motorists to travel between Beresfield and Melbourne without encountering a single set of traffic lights.

If connecting with the M2 towards Sydney's CBD, motorists will also bypass 40 sets of traffic lights on the Pacific Highway.

Northconnex tolls will be $7.83 for cars and $23.50 for heavy vehicles.

Parliamentary Secretary for the Central Coast, Terrigal MP Adam Crouch, said the three projects would "make the commute of thousands of motorists faster, easier, safer and more reliable".

"Transurban has advised [NorthConnex] will be ready in the third quarter of 2020," he said.

"Transport for NSW will keep motorists and the community informed, and communicate the opening date as soon as it's confirmed.

"Until then, work on Australia's longest and deepest road tunnel is continuing to provide vital jobs and significant economic benefits to suppliers, manufacturers and supporting sectors."

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