The Durngate parking lot, off the North Walls, was open for at least a week until County Council closed it late Wednesday.
Temporary entrance to the fencing bars and there is now a “closed” sign in place.
Yesterday, two police cars were parked at the entrance, but they are not believed to be related to the enforcement of the closure.
The 80-space car park was opened following the completion of the flood defenses on one of the Itchen streams at the rear of the site. But no cash dispenser is installed yet.
During most of its unofficial opening, the parking lot was little used.
In a statement, Hampshire County Council said: âI can confirm that the Durngate car park remains closed. It was closed while flood mitigation work, as well as construction work on the neighboring Trinity House, was undertaken.
âThe parking area still needs to be rehabilitated and minor landscaping work is also needed. The road officials are currently organizing the implementation of more robust measures to strengthen the closure of the parking lot.
A notice on the closing sign at the entrance read: ‘Access to the Durngate car park is to be physically blocked on July 14 and will reopen to the public when parking meters are installed.
“We ask you not to park in this car park before this date (of reopening). Any vehicle left in this car park after this date (July 14) may be trapped because the access will be closed and arrangements will have to be made for its release. ”