The Office of Management and Budget said yesterday that the government is in no position to put together a regulatory budget, an idea which has considerable support among leading economists allied with President-elect Ronald Reagan.

The budget idea, which has been kicked around the federal regulatory apparatus for most of the Carter administration, will not work, OMB said in a report entitled "Improving Government Regulations." A regulatory budget would create a mechanism for assessing the national cost of federal regulations.

The report was an effort to evaluate the effectiveness of a number of programs, including the Carter administration's widely touted executive order forcing executive branch agencies to consider the costs and benefits of new rules before they are issued in final form.

While admitting that a need exists to get a better handle on the true costs of federal regulation on the private sector, the report says that more work needs to be done in having agencies identify and group their regulations. OMB itself has circulated draft legislation that would set up a regulatory budget plan modeled after the federal budget act.

"the state of the art of measuring for the cost of regulations is far behind the rhetoric," OMB said. "We mention it here only in recognition of the growing public interest in the need for something like a budget to help control the costs of federal regulation."

"Regulatory budget today is a buzz-word -- a concept beyond the government's present abilities," OMB said. "Considerable OMB attention will be devoted to these issues in the coming months."

Republican economists such as James Miller of the American Enterprise Institute and former Treasury department official Murray Weidenbaum of the Center for the Study of American Business often have said that the budget plan would give the federal government a needed planning tool in assessing the impact of regulation on business.

But environmental activists, for example, have said that it is impossible -- if not unfair -- to try to quantify the costs of a health and safety regulation, such as the ones administered by the Occupational Safety and Health Administration.

In its report, OMB said it has prepard a mechanism for putting together a "regulatory cost accounting system."