Despite protests from its staff, the National Conference of Christians and Jews will not change its plans to give President Reagan its humanitarian award at a March 23 dinner in New York, spokesman Harry Robinson said yesterday.

Members of the national and regional staff of the non-profit human relations organization said in a confidential memorandum that the award would reflect agreement with Reagan's economic and social policies, according to a published report.

Robinson said the decision to honor the president with the Charles Evans Hughes Gold Medal "for courageous leadership in governmental, civic and humanitarian affairs" was made by conference President David Hiatt and national chairman Irving Mitchell Felt in conjunction with lay leaders of the group. It is a fait accompli that will not be affected by the memorandum, he said.

He quoted Hiatt as saying the award is "non-political," presented to Reagan "as a person and as the president of the country."

The award is named for the chief justice of the United States from 1930 to 1941 and a co-founder of the inter-religious organization.

The memorandum also said the conference's decision "is in clear violation of published selection procedures," because policy stipulates that no award be given without the approval of the National Awards Committee, which includes three staff members.

Robinson, spokesman for the conference, said procedures have changed and that such decisions now are made by the lay members of the conference, who hold top management positions.

"Quite naturally some people are going to be upset. We have a democratic organization and people have the right to express their feelings."

The staff committee, made up of the conference's professional workers, said it would submit its memo to the conference leadership this week.

A top conference official who favors the award reportedly said that 90 percent of the organization's 120 professional staff members oppose granting the award to Reagan, but it was not known how many signed the memorandum.

But Robinson said even though some staff members were upset about the decision, it "doesn't change anything."

Three previous presidents received the award, but the dinners honoring Dwight D. Eisenhower, Harry S. Truman and Gerald R. Ford came after the end of their terms as president.