"From this president, there will never be a single gesture that deepens our current difference," Kirchner said during her inaugural speech to Congress Monday after having been sworn in as Argentina's first elected woman president.
She takes over after her husband, Nestor Kirchner, who stepped down as president after one term.
Straining relations between the two South American countries is a pulp mill on the shores of a jointly managed river. Argentina claims Uruguay never informed it about the construction of pulp mills along the river, Mercopress reported Monday.
Uruguay denies the charge and the case was taken by Argentina to the International Court of The Hague, which is expected to rule on the matter in 2009.
Kirchner said Argentinians will continue to see Uruguayans "as our brothers; let there be no doubt about this."