The Labor Ministry rule announced Tuesday also says the "agents" will be able to offer Internet access at some point in the future.
Cuba has some 1.2 million fixed phone lines and 1.8 million cellphones for a population of around 11 million. Many domestic land lines are not equipped for making long-distance and international calls, though they can receive them.
The "agents" will have to charge the same as what state telecom monopoly Etecsa charges customers, with the company paying them a commission. International rates in Cuba can run as high as several dollars a minute.
The measure also authorizes the contractors to sell prepaid cellphone cards, collect phone bill payments and even offer Internet.
As with a number of the 200 or so areas of independent economic activity now allowed under President Raul Castro's reforms, the resolution seems geared toward regulating and taxing activities that are already common in the informal economy.
Cubans with long-distance lines already let neighbors use their phones for a fee, and there's also a black market for the sale of dial-up Internet minutes.
According to government figures, only 2.9 percent of Cubans say they have access to the full Web, though the real figure is believed to be higher accounting for the black market. More Cubans do have access to a domestic Intranet where they can browse homegrown websites and send and receive email.
Home Internet accounts are still closely restricted, though authorities have said they intend to begin offering them to the wider public next year.
Recently, authorities opened more than 200 public cyber-cafes across the island that charge about $4.50 an hour.