Permission to begin work on the car park stalled in the Autumn after then Councillor Nick King expressed reservations at the unsatisfactory number of parking spaces in the plans.
Mitchell offered to increase the number of spaces from 400 to 470 this month, but was rebuffed by Bournemouth council.
"With limited space around the park and the understandable concerns of local residents over increased street parking in the area, it doesn't make sense to lose such a large area that could be used effectively for match day parking," Mitchell said.
"We are still on track for a springtime completion, but we had earmarked a big empty area of land between the car park and the south stand for an extra fifty parking spaces. The land is currently destined to be an empty tarmac area, and that is why we are a little disappointed that our proposals have been shunned.
"It will look quite odd to supporters when the car park is full on a matchday and there is a section of empty space, but we have repeatedly tried to persuade the council to allow its use but have been told no.
Chairman Mitchell was quick to start work after the Cherries were granted a licence to carry out resurfacing on the Kings Park lorry park in early December.
Whilst the car park capacity has been temporarily lowered in the months during the work, the Cherries have increased efforts to secure parking elsewhere around Kings Park and Boscombe, including the Sovereign Centre and local schools.
Mitchell was adamant that the club were doing all they can to avoid matchday parking impeding local residents.
"In view of supporters parking in the streets surrounding the Goldsands Stadium increasing, the club will endeavour to make sure street parking is done correctly and the upmost consideration is given to residents.
"This is one of the most important issues for us. We were hoping that the extra 70 extra spaces would ease this. Now we are forced to find other avenues to help our supporters and our neighbours."