"You then ask yourself whether this is really a free float," a dealer at a Harare bank said.
The central bank says it removed the 1:1 dollar peg to benefit exporters who previously surrendered a portion of their dollars at the official rate.
Exporters, including miners who earn the most dollars for the economy, can now sell part of their U.S. dollars at the 2.5 rate. But they can only keep dollars in local foreign currency accounts for 30 days, after which they are required to sell on the interbank market.
This, the central bank hopes, will create a ready pool of dollars for importers and the government.
But some analysts are sceptical, saying exporters should be allowed to keep all their dollars and only sell when they need to, if Zimbabwe is to attract foreign investment.
"This is not much of a currency reform. They just merged the RTGS (electronic dollars) and bond notes and devalued the exchange rate, but everything remains the same," said Tony Hawkins, professor of business studies at the University of Zimbabwe.
In another sign of the acute dollar shortages, long queues resurfaced at petrol stations this week where fuel is supplied by government purchases in the U.S. currency.