It will mean that traffic travelling from Newlyn will have to make a marked detour into Penzance via Lidden Road and Alverton.
The road is being closed for works to remove historical flooding issues in the area and is being carried out by Molwin Homes as part of its major development project currently taking shape on the Promenade.
Jason Bardell, of Molwin Homes, said: "The £700,000 works will not only bring our development out of the 100 year flood plain but will remove some other vital areas from the flood plain, namely the Co-Op and Lidl stores, together with the majority of the Promenade.
"As part of our development, it is a requirement to improve the culvert which historically has, contributed to flooding causing severe damage and inconvenience to this area and the residents of Newlyn for many years.
"We would like to thank all residents and users in advance for their understanding of this much needed improvement work.
"We hope they are in agreement when we say this will be a short term inconvenience for a benefit for many years and generations to come."
The Co-Op and Lidl Wherrytown stores will be open as usual during the improvements.
Customers will still be able to access both stores from the Penzance side without any obstruction. Pedestrian access will be available to and from Newlyn and Penzance.
On top of this investment, Molwin Homes are also contributing £200,000 to the improvement of the Promenade itself.
article copyright THE CORNISHMAN