Some people may be skeptical about President Reagan's federalism initiative returning power and responsibility to the states. But big business takes it seriously and is cozying up to state government officials as never before.

A conspicuous feature of the National Conference of State Legislatures (NCSL), which wound up its five-day meeting here today, is the number of people with convention badges identifying themselves in the "business" category.

Many are members of the State Government Affairs Council (SGAC), an organization of top lobbyists and public affairs officers from 88 major corporations and trade associations, which meets annually with the NCSL and has a variety of joint projects with it.

This year, SGAC underwrote the costs of two of the NCSL plenary sessions, dealing with the economy and technology. Later this year, the business lobbyists will play host at two weekend seminars for legislative leaders and key staff members.

Gordon D. McKay, vice president of New England Mutual Life Insurance Company, who took over here this week as president of SGAC from Bank of America executive Fred J. Martin Jr., explained why the business lobbyists are so visible at the legislators' meeting.

"We see the return of power to the states," McKay said "and to the extent the states are better run, we will all benefit."

SGAC also is underwriting a project with the National Governors' Association to analyze opinion poll data.

The lobbyists' organization was formed in 1975, just a year after NCSL itself came into existence. According to its charter, its purpose is "to work with the states to improve the effectiveness of state administrative, legislative and regulatory processes," and to "strengthen interaction and understanding between the private sector and state government."

From the beginning, its meetings have coincided with NSCL's and in some ways have merged.

While SGAC offers no ongoing financial subsidy to the legislators' organization, it does underwrite part of its program costs. This year, for example, SGAC paid the honorariums and expenses for a panel on economics featuring Washington lobbyist Charls E. Walker and economic consultant Michael Evans, moderated by Newsweek contributing editor Jane Bryant Quinn. It also arranged and financed a panel on biotechnology featuring industry and university experts.

McKay said both programs were set up at the request of NCSL leaders. Mary Jane Gallagher, the NCSL publicist, confirmed this and said it would have been impossible to finance such panels from the $150 registration fees paid by the legislators and legislative staff members attending the convention.

SGAC itself did no entertaining of the 2,500 delegates, but many of its member companies and associations maintained their own hospitality suites and sponsored receptions.

Gallagher said, "the lobbyists have always swarmed around this meeting. What we have tried to do is move them into more substantive areas, rather than just the social things."

In recent years, SGAC has been asked to provide staff assistance and witnesses for NCSL committees, particulary in technical areas of regulatory policy. This year, for the second year in a row, it will arrange seminars for key legislators and staff.

In October, a group of corporate training officers will conduct a three-day seminar on administrative skills for legislative staff members at a resort in Kentucky. In November, a seminar on labor market trends will be held at a Florida resort for legislative leaders.

Transportation costs for these seminars are paid by the legislative members and employes, but their housing, food and entertainment costs are subsidized, McKay said, by higher registration fees charged to the corporate participants.

Both the NCSL meeting and the smaller seminars, where 50 to 100 corporate officials work with legislators or legislative staffers, offer opportunity for close contacts.

McKay said SGAC itself "does no lobbying," but he readily conceded that its members--whose companies pay $1,500 a year in dues to support the organization--"obviously may use these meetings to lobby their own positions. Any time in your life you develop a relationship with somebody, sometime down the road, it may be of value to you."

The list of members, including major manufacturing, food, beverage, retail and insurance companies, has been growing--as has SGAC's range of joint activities with state officials. McKay pointed out that SGAC last year agreed to underwrite a new project on public opinion research for the National Governors' Association Center for Policy Research.

The project analyzes polling data from a variety of sources on public policy questions and publishes a quarterly newsletter called, "State Opinion Report."

Stephen Farber, the governors association's executive director, said there is no underwriting of convention programs by SGAC. Several years ago, after adverse publicity about lavish corporate entertainment at the annual governors' conference, the governors decided to finance their own social events through social fees charged to state officials, reporters and lobbyists attending the annual meetings.

Both organizations, however, have host committees for their conventions, and local businesses often underwrite the costs of those companies in bringing the convention to a particular city or state.

Kansas state senate president Ross O. Doyen (R), the outgoing president of NCSL, said, "I don't have any concern about these people (the SGAC members) participating in our meeting. I think it's excellent they take this interest in us. . .we work hard during the day, and sitting down with business executives broadens your perspective."

Illinois senate president Philip J. Rock (D), the chairman of this year's host committee, took a similar view. "The relationship with the private sector is a necessary one," he said. "Obviously, they bring their concerns to us, but it's a healthy relationship. We need to be well-informed."