AXA Wealth, a sponsor of the Institute of Financial Planning, has warned of consumer detriment stemming from the FSA's platform paper.
The paper CP12/12 states that the FSA is proposing to ban payments from product providers to platforms.
AXA Wealth feels all payments and rebates should be kept and that the changes will put pressure on the industry's IT systems.
It also cited risks from liquidity management problems as clients need to find new funds to pay for platform services and increased complexity of the clients' tax position.
David Thompson, managing director of marketing and distribution, said: "AXA Wealth's view is that all payments and rebates should be retained. We believe this represents the most practical way to discount the cost of investments accessed via a platform whilst ensuring transparency of other charges.
"This change will put more pressure on the industry's mandatory IT development capacity, as companies go into 2013 facing another major development to make in order to comply with new rules. There is serious risk, at industry level, innovation may be stifled."
The Investment Management Association was also concerned about the effect on investors.
Julie Patterson, IMA director of authorised funds, said: "The splitting of payments will require the industry to overhaul its administration processes and mean, in the future, more firms will be administering much smaller sums of money.
"There is a risk the end cost of investing could rise as a result. There needs to be an efficient mechanism that facilitates these payments in a fully transparent way."
She warned that, contrary to FSA expectations, some investors may even be deterred by the new rules.
"There is also serious concern that those with modest sums to invest will be deterred by these new measures and ordinary investors will no longer be able to benefit from bulk discounts currently secured by intermediaries that aggregate the orders of many investors."