Northern Beaches Council will temporarily reopen Macpherson Street Warriewood, which is currently undergoing extensive upgrades worth $10.2 million.

Council's Deputy General Manager Ben Taylor said the move to reopen the road will ease traffic congestion for residents and Warriewood Square shoppers over the busy Christmas/New Year period.

"Essential investigations with respect to geotechnical conditions and service locations have been completed on schedule," Mr Taylor said.

"Whilst temporary service relocations works are being commissioned with specialist service authority contractors, Council sees an opportunity to reopen the road to the public from today (16 November) with temporary traffic controls in place for the ongoing service relocation works. This will ease congestion whilst the works continue.

"Full construction works will begin to impact the whole road from 9 January when we'll need to close this section of Macpherson Street again until the works are completed in October 2017," he said.

Mr Taylor said the works will deliver vital improvements to the area, ensuring a safe flood evacuation route for Warriewood Valley.

"Improved creek flows and natural environment enhancements, a new 12 metre-long bridge, road upgrades and shared pathways are just some of the other benefits the community will see once the project is completed," he said.

"This major upgrade project remains on schedule, with the road to reopen permanently in early October 2017."

Council will notify local residents, affected businesses and services by letter of the temporary opening, and sign boards in the area will also provide updates.

State Transit Authority bus detours and local shuttles will remain in place due to the limited street access and relatively short reopening period.