Sheikh Abid Gulzar said the promise was made when the prime minister and chancellor George Osborne visited Eastbourne shortly after a huge blaze destroyed the pier’s amusement arcade in July 2014.
The fund is managed by Eastbourne Borough Council, which has used it to boost the resort’s tourist trade with displays and events.
Gulzar told the Eastbourne Herald Cameron had said the money was to go to whoever owned the pier, rather than the town as a whole.
He said: “I spoke to David Cameron when he visited our great town, and he left me under no illusion that this money would go to whoever owned the pier, whether that be me, the previous owner or indeed anybody else.”
Brett McLean, chair of East Sussex Economy Advisory Board, backed Gulzar and calling on the council to use what remains of the fund to support the pier and its new owner.
In a joint letter to council chief executive Rob Cotterill and David Cameron, McLean said: “Following a recent site visit to Eastbourne Pier, I can clearly see that The Lions Group under Mr Gulzar have undertaken major cosmetic refurbishments and some minor structural improvements using their own resources.
“I can’t help but wonder what happened to the £2m cash boost promised by Her Majesty’s Government when the prime minister and chancellor of the exchequer visited Eastbourne.”