The Chamber of Mines said gold output slumped to 2,624 kg between January and July this year compared to 4,686 kg during the same period in 2007.
Miners sell their gold to the sole purchaser and refiner, Fidelity, a central bank subsidiary. They receive 40 percent of their earnings in foreign currency.
"Issues of concern include delays in paying gold producers their U.S. dollar revenue. Data at hand indicate that there are some producers that have not been paid for deliveries made in 2007," the chamber said in a statement.
Zimbabwe’s mining sector was rattled last year after the government introduced a law compelling all foreign-owned companies, including mines, to sell 50 percent of their shares to locals as part of an empowerment drive.
Foreign investors have withheld funding for expanding existing operations, worsening the plight of a sector hit by mine closures in the last seven years and soaring costs.
Gold accounts for a third of Zimbabwe’s export earnings after the collapse of commercial agriculture, which some critics blame on President Robert Mugabe’s policy of seizing white-owned farms to resettle blacks.