Irish nationalists and Argentinian groups said today they will harass Britain's Queen Elizabeth II throughout her 10-day visit to the United States with anti-British demonstrations, airplane banners and even a small boat flotilla on her arrival in San Diego Saturday.

"We are against this royal visit," said Suzeanne McGee, an Anaheim representative of the Orange County chapter of Irish Northern Aid.

"We will not show respect for the wealthiest welfare recipients in the world. We will not bow down to the sponsors of evil."

Officials of Irish Northern Aid, a U.S.-based group supporting the aim of the outlawed Irish Republican Army to unify Ireland without British influence, said they were organizing demonstrations in San Diego, Los Angeles, Santa Barbara, San Francisco, Sacramento, Stanford, Yosemite Valley, Seattle and other stops the queen and her husband, Prince Philip, are scheduled to make.

McGee said she did not expect any violence, however. "The queen is safer here than in her own country," she said.

The White House is worried about the demonstrations, administration officials acknowledged. One senior official expressed concern that the demonstration in San Francisco while the presidential party is there would dominate news coverage at the expense of Reagan and the queen.

This official pointed out that "this was a different kind of demonstration" than the ones Reagan usually faces. His point was that the president enjoys significant support from Irish-Americans and does not like to be cast as being insensitive to Irish concerns.

McGee was joined at a news conference by Luciano Pruneda, a representative of the California-based Argentine coordinating committee, who said he expected many of the 55,000 Argentinians in the area to join the protest against the royal visit.

He said group wished to dramatize "the accumulating acts of provocative moves of the British Empire," particularly its "massive deployment of military power" to retake the Falkland Islands, or what Argentina calls the Malvinas Islands, last year.

Demonstration leaders said they expected 5,000 to 10,000 people at a Thursday rally in San Fransisco. Seamus Gibney, Irish Northern Aid West Coast demonstration coordinator, said, "Everywhere the queen goes Irish Northern Aid agents will make an appearance . . . . She is going to Yosemite for a rest. That's what she thinks."

McGee said that although her organization wants British troops out of Northern Ireland and wants that predominantly Protestant area reunited with the predominantly Catholic Republic of Ireland, the group does not raise funds for the IRA. Asked if Irish Northern Aid condoned IRA terrorist violence, McGee said, "People once called George Washington a terrorist."

British officials have been sensitive about security in the United States for visiting royalty, particularly after rumors, later discounted, of an IRA plot to kill Princess Margaret in 1979 and raucous demonstrations against Queen Elizabeth's son, Prince Charles, in New York in 1981.