Democrats leaders branded Republican White House hopeful Mitt Romney's survey of hurricane damage in Louisiana the "height of hypocrisy" Friday, alleging his policies would gut disaster funding.

"Under a Romney-Ryan administration, we would not have been prepared to respond to Hurricane Isaac," Senate Majority Leader Harry Reid said, as Romney's plane made a surprise stop in storm-ravaged New Orleans.

Romney's trip, staged one day after he formally accepted the Republican Party's nomination to oppose Democrat Barack Obama in November's presidential election, made waves because he had visited before the incumbent.

A sitting commander-chief is able to issue emergency declarations, unleash federal funding and deploy reservist troops in a way that would have far more impact on a disaster zone than could a candidate.

Obama visits Louisiana on Monday.

Reid called out Romney for backing the budget plan of his vice-presidential running-mate Paul Ryan, which was approved by Republican lower house lawmakers earlier this year, and which would slash federal disaster funding.

"If Paul Ryan and his fellow House Republicans had succeeded in blocking disaster relief last fall, there would have been no aid for the victims of Isaac today," he said.

"It is the height of hypocrisy for Mitt Romney and Paul Ryan to make a pretense of showing sympathy for the victims of Hurricane Isaac when their policies would leave those affected by this disaster stranded and on their own.

Reid's was one of several parries in a sparring match between the Romney and Obama camps.

Senator Mary Landrieu, a Louisiana Democrat, said she welcomes Romney to her state "so he can see firsthand the devastation caused by Hurricane Isaac.

"I hope as he witnesses recovery in action, he will reflect upon his party's approach to funding disaster response," she added, citing the same gutting of programs mentioned by Reid.

"My hope is that governor Romney will leave Louisiana realizing that such an approach is overly bureaucratic, unworkable, and terribly unfair."

Romney made a low-key visit Friday that included a briefing by Republican Governor Bobby Jindal.

He also traveled in a high-water truck, accompanied by National Guard members, and passed submerged gas stations and flooded homes en route to an expected stop at an emergency command center in Lafitte.