...Minister Aleksander Szczyglo said on Monday.
Washington wants to place 10 missile interceptors in Poland and a radar system in the Czech Republic as part to offer protection from potential attacks by what it calls "rogue regimes" such as Iran.
The U.S plans have sparked a row with Moscow, which fears the system could, at some stage, be converted for offensive use against Russia.
Asked by the weekly Wprost newspaper when the Polish part might be finished Szczyglo said: "That depends on the negotiations. In 2011, 2012 at the earliest."
The United States is currently in talks about the shield with the Polish and Czech governments.
The proposals have also raised concern in Poland, where the majority of Poles oppose the plan due to fears the country could become a target of a terrorist attack.
But, Prime Minister Jaroslaw Kaczynski is committed to placing part of the shield on Polish territory saying it would bring the country greater security.
Poland is a strong ally of the United States, with military forces committed to the U.S.-led mission in Iraq and the NATO operation in Afghanistan.
Keywords: POLAND SHIELD/
[WARSAW/Reuters/Finance.cz]