Mayor Giuliani said yesterday that he was "prepared to do anything" to help President Clinton beat back the GOP Congress' attempt to repeal the assault weapons ban.

And he offered this advice to Clinton: "Go on the offensive" by seeking even stiffer federal gun control laws.

"Instead of dealing with the rollback on the ban that's in effect, extend it and seek uniform laws on gun control throughout the country," said Giuliani at a City Hall news conference.

His comments came in response to Clinton's appeal during an exclusive Daily News interview Sunday for the mayor's aid in fighting his fellow Republicans' efforts to lift the ban on 19 semi-automatic assault weapons.

Giuliani said the President personally thanked him Sunday for his public support last year for the ban a position that bucked the national leadership of his party.

The mayor promised yesterday to campaign actively to preserve the weapons ban, including trying to keep Republican lawmakers who backed it last year from changing their positions.

If Congress still should repeal the ban, Giuliani said he would support a presidential veto.

The measure before the House not only would repeal the ban, but override state and local gun licensing laws by permitting people to keep firearms in their homes for self-defense.

In making his call for more federal control of guns, the mayor pointed out that 90% of the guns in the city come in illegally from the outside.