Two percent of work had been done at the Chalong underpass when work stopped at Christmas. Digging will resume at Chalong and Phuket's other underpasses on January 3.
Authorities predict heavy traffic every day in the New Year.
The Samkong underpass is not likely to be complete by January 12, when the contractor faces fines of two million baht a day.
Existing drains have proven too small to carry away the water that falls around the Tesco-Lotus intersection so larger drains are being installed.
Work on the Bangkoo Underpass, where Phuket's busy north-south Thepkasattri Road meets the bypass road, is 24 percent complete.
Detours around the site flow reasonably smoothly and managers predict the underpass will be complete before the contract ends in September, 2017.
Work is 17 percent ahead of schedule.
Earlier this year Phuket's first underpass opened at the Central Festival intersection. A fifth underpass at the turnoff from Thepkasattri Road to Phuket International Airport has yet to start.