A group of moderate House Republicans yesterday released a budget proposal for next year that would impose an across-the-board freeze on most government programs, including defense, to reduce the federal deficit by $51 billion next year.

The proposal would not touch Social Security and would preserve most of the programs targeted for elimination by President Reagan in his 1986 budget.

The GOP lawmakers, known as the " '92 Group" for the year in which they hope Republicans will take control of the House, are mostly from Northeast, industrial and farm states. They said their budget made deeper reductions in the deficit than Reagan's but distributed the cuts more equitably.

"The deficit . . . doesn't give anybody the right to destroy the government," said Rep. Stewart B. McKinney (R-Conn.).

The Democratic-controlled House Budget Committee is waiting until the Republican-led Senate finishes its work. However, Democrats on the Budget Committee have agreed in private to about $46 billion in deficit reductions, primarily through a budget freeze similar to that being proposed by the moderate Republicans.

The Congressional Black Caucus also released its proposed 1986 budget yesterday. The caucus would reduce the deficit by $39.2 billion by a combination of program reductions and $27.7 billion in new taxes -- primarily the closing of loopholes benefiting higher-income taxpayers and the delay of indexing. So far, the caucus is the only group willing to support a tax increase.

The Republican moderates' budget proposal would cut the federal deficit, now hovering above $200 billion, in half over three years to over $100 billion.

The group would terminate a few programs, including the Synthetic Fuels Corp., federal crop insurance subsidies, most of impact aid paid to local school districts, and general revenue sharing, which would be phased out over three years.

At the same time, it would cut, but not eliminate, other programs Reagan had slated for termination, such as Urban Development Action Grants, rural electrification loans, Amtrak, and the Small Business Administration. It would allow an increase for inflation for many programs for the poor.