A spokesman for the club said: "A figure in the region of £5m is needed to complete the first phase of development, and that money may also be used for work after that first phase.
"There is still a lot of work to be done. The ground will be nowhere near finished by the start of the season, and the pavilion will not be used for some time." But the spokesman also hinted that the club's new multimillionaire chairman Rod Bransgrove will provide the extra cash to fund the project.
He added: "The new chairman has plans to progress." Hampshire's cricket team will be forced to use temporary dressing rooms when the season begins in the spring.
The project team includes contractor Henry Boot and engineer Buro Happold.