AT&T said this week it will spend more than $120 million to beef up its wireless network in Georgia this year.

A taxpayer subsidy will pay for some of the improvements, such as the addition of more than 80 cellular sites in metro Atlanta and other parts of Georgia. Two new towers on Cobb Parkway and Windy Hill Road will be among the key additions.

The company also will strengthen its high-speed voice and data network, called 3G, in Columbus and Savannah.

"The 3G expansion brings more of our high-speed capabilities to more customers," said Rachel Kutz , AT&T's executive director of network services for Georiga.

Further, the company is adding cell towers and expanding its wireless coverage in Athens, Bainbridge, Macon and Milledgeville.

AT&T is doing this work with tax credits from Georgia's Business Expansion and Support Tax Act (BEST) as well as from the Port Investment Credit Bonus, company spokeswoman Sage Rhodes said.

Neither the company nor the Georiga Department of Revenue would say how much AT&T received in tax breaks. The revenue department cannot disclose any income tax-return information, said Edward Many , the department's deputy adminstrator for tax administration.

Bill Bozarth, executive director of Common Cause Georgia, said AT&T should disclose the dollar figure so taxpayers can fully understand where their money is going.

"What bothers me is that they can't tell you how much money is involved there. Why does that need to be a secret?" he said.

The state Legislature established the tax credits in the 1990s, Many said.

Companies can receive the credits either for creating jobs or for making a business investment.

Atlanta-based BellSouth Corp., which AT&T bought in late 2006, received $17 million in tax credits from the state in 2000 to expand its high-speed Internet network into rural areas. The tax breaks were given at a time when BellSouth and other major telecom companies were loathe to provide the speedier service to rural communities because of the cost.

According to information from the state Department of Community Affairs' Web site, companies that want BEST credits must have operated in Georgia for at least three years and invest at least $50,000. They would receive a tax credit of 1 percent to 5 percent depending on the economic health of the counties where the investments are made.

To get the port-related credits, a company has to be shipping something to or from a state port as well as meet the BEST act's requirements, Many said. They are worth 5 percent to 10 percent depending on various factors.

Rhodes said in an e-mail that AT&T is using the Savannah port.

"These tax incentives help AT&T focus technology investments to reach as many Georgians as possible," she said in a separate e-mail.