Republican mayoral candidate George McDonald can keep filling his war chest with donations that are larger than city law allows, but he can’t spend a dime of it until a lawsuit against the city’s campaign-finance law is concluded, a Manhattan judge ruled yesterday.

“This was a big victory,” McDonald’s campaign manager Craig Parker told The Post outside Manhattan Supreme Court.

“The important thing is I get to raise the money,” McDonald chimed in.

McDonald has been accepting contributions in excess of the city’s $4,950 limit on donations from individuals. He says the city law shouldn’t apply to him because he’s not taking matching funds.