Ah, St. Patrick's Day in the city: the green stripe painted on Fifth Avenue, the echo of endless bagpipes, the annual March infighting among New York's Irish.

After past controversies over an IRA-linked grand marshal and the exclusion of gay groups from marching, this year's hostilities pit organizers of the 246th parade against the city's firefighters — their second battle in two years.

St. Patrick might have driven the snakes out of Ireland, but he'd find it near impossible to eliminate controversy from the nation's oldest and largest celebration of all things Irish.

John Dunleavy, president of the parade's organizing committee, ignited this year's brouhaha by moving the FDNY from its traditional spot at the front of the parade to the middle of the pack.

Dunleavy then created a separate brew-haha by complaining that firefighters show up drunk for the parade — and continue drinking all day while in uniform.

Fire officials, along with city officials, were quick to strike back at Dunleavy on both counts.

"He's made a huge mistake in trying to brand all New York City firefighters on something that he says he saw," said Uniformed Firefighters Association head Steve Cassidy about the drinking charges. "It's nonsense."

Uniformed Fire Officers union head Peter Gorman called Dunleavy's comments "the ultimate slap in the face" to those firefighters who turn out to march — including some whose participation is slowed by injuries suffered on the job. Firefighters march carrying 343 flags, one for each FDNY member killed on Sept. 11, 2001.

City Council speaker Christine Quinn and Mayor Michael Bloomberg were among those perplexed by the FDNY's removal from its usual starting point.

"I think it is ridiculous and absurd that the organizers of the parade are moving New York's fire department back," said Quinn. "I think they should immediately move the fire department to the spot that they've historically been in the first place."

The FDNY, along with the Police Department the Fighting 69th Infantry band, usually march at the front of the parade, which draws about 2 million people each March 17.

The crux of the marching order dispute between the FDNY and parade organizers was last year's appearance by New Orleans firefighters with the New York contingent. Organizers said the parade, with its 150,000 marchers, was delayed 35 minutes while the Louisiana group unfurled a banner thanking New York for its aid after Hurricane Katrina.

The slowdown infuriated parade organizers, and Dunleavy said last week that the firefighters were "a law unto themselves" and needed a reminder about who was running the parade.

Bloomberg felt the decision to relocate the FDNY contingent was inappropriate. "It didn't make any sense to me," he said.

Dunleavy, who did not return phone calls for comment, made his remarks about drunken firefighters in a rare interview with the weekly Irish Examiner USA.

Quinn, who is openly gay, opted to march in Dublin this year rather than participate in a New York parade where gays may not walk under their own banner. The fight over the banishment of gay groups by the parade committee began in 1991, and has yet to abate.

But gay marching is not the only issue.

Two years ago, some firefighters boycotted the parade when department officials barred them from wearing their customary green berets. In 2002, there was a dispute over the best way to honor the victims of the World Trade Center terrorist attack. And in 1983, former IRA soldier Michael Flannery served as grand marshal.