The eastern spur of Lariggan Road will be closed from April 20 until June 26, and traffic lights are to be put in place at the works on Western Promenade Road.
Darren Edwards, streetworks coordinator for Cornwall Council, said: "We will be using traffic lights so the work can be done without having to shut down the main road into Newlyn.
"This was one of the provisions put in place for the work to be completed at this time of year."
He explained how these measures would, hopefully, alleviate the problems that occurred in October when Western Promenade Road was closed as part of the original contractor's plans.
The road closure caused access problems for residents and businesses in Newlyn after the main route into the town was blocked for the work.
He added that the traffic lights could be operated manually in order to reduce congestion at busy times, and said they would be removed over both May bank holidays to limit the project's impact on tourism-based businesses over these periods.
Building work on the culverts was recently taken over by the Truro-based company H20K systems after Molwin Homes pulled out of the development last year.
Improving the flood defences had been a requirement of Molwin Homes' £35 million Waterfront regeneration scheme to build new homes on the seafront at Penzance.
Marcus Willcox, contracts manager for H20K systems, said: "We are now the main contractors on this job for the new owners of the site."
"What we have done so far is move the culverts into their new site in the compound in preparation for when the job begins."
Molwin Homes went into administration last year while working on the Waterfront development.
This led to the work on the flood defences being postponed as a new contractor was found to complete the project.
The original design for the project had been drawn up by H20K systems and it had been acting in a supervisory role, overseeing the work being done by Molwin Homes.
Mr Willcox told how this experience put them in a unique position when it came to taking over the works.
article copyright THE CORNISHMAN