The call from the chairman of the body brought together to promote the Greater Brighton City Region economy comes as Highways England is part-way through an eight week consultation on making improvements to the heavily-congested stretch of road through Lancing and Worthing.
Commenting on the plans, Cllr Andy Smith welcomed the promise of transport infrastructure investment from government, particularly with planned growth along the wider A27 corridor in the pipeline.
However, he said he feared that the £69 million proposal did not go far enough in creating a lasting solution to the lack of capacity on this major east-west route and called for other options to be part of the consultation.
Cllr Smith, chairman of the Greater Brighton Economic Board, said:
"The A27 is crucial to the wider Greater Brighton area, not only as an arterial route for freight, but as the main east-west transport corridor for the 700,000 people that live in the City Region.
"The right sort of investment in the few miles of highway through Worthing and Lancing could have a major impact on the Greater Brighton region as a whole, boosting growth and creating jobs.
"While we do welcome Highways England wanting to invest in the area, it does appear that the proposed solution is far from the lasting one that residents and businesses have been pushing for in the last 20 years.
"A failure to invest in our region's infrastructure now can only set Greater Brighton back from reaching it's full potential in the years to come."
Government officials have spent more than 20 years trying to find a solution to the lack of road and junction capacity on the A27, which is the only east-west trunk road south of the M25.