The government was planning to launch the new service in September but the three companies with Belgian 3G mobile phone licences requested more time late last month.
"The 3G network isn't there yet, the machines aren't ready, so the minister agreed to a delay," said Regine Van Tomme, a spokeswoman for telecom minister Rik Daems.
Holding licences to operate the services are France Telecom's Belgian mobile division Mobistar, the former state monopoly Belgacom and Vodafone Group's Proximus, and Dutch operator KPN Orange's Belgian unit of the same name. Together they spent £277m last year buying their licences. A fourth licence remains unsold.
"We are satisfied that we now have a year more to build the network," said Jean-Luc Van Kerckhoven, spokesman for Proximus. "If we had to launch this in September then 3G would have been a disappointment. With an extra year we will be able to make it a real commercial launch."
"It is wise to take more time and get it right," he added. Swedish mobile operators last month became the first in Europe to open their 3G networks, but their effort was symbolic as they still aren't offering any services.
The 3G technology will provide services such as high-speed Internet connections and video downloads to mobile phones.
The few 3G handsets on the market come from Asia. NEC supplies NTT DoCoMo's limited service in Japan. But European manufacturers won't begin catching up until later this year. Finland's Nokia plans to start shipping 3G handsets in the third quarter of this year, with volume deliveries beginning in the fourth quarter, said Nokia spokesman Tapio Hedman.
Delays in the construction of the network have partly been due to regional governments' reluctance to permit the installation of radio masts. The phone companies with Belgian 3G licences threatened to sue the governments of Wallonia, Flanders and Brussels last November.
Van Tomme said the problem with local governments is almost overcome. "The talks are going smoothly. We will find a solution for the whole country very soon," she said.