The Department of Energy risks imposing "an unnecessary reporting burden" on the oil industry and "inundating policymakers with irrelevant data" under its proposed financial reporting system, the General Accounting Office said yesterday.

At the same time, the system could delay "the collection of relevant information on which energy policy should be based," according to GAO. The GAO report criticized the Department of Energy for failing to document the needs and uses of the financial information it wants from oil companies.

Spokesmen for several major oil companies similarly criticized the proposed financial reporting system at a public hearing July 17.

The GAO assessment came in a report issued yesterday that agency officials had not seen the GAO analysis and had no comment.

The Department of Energy has orders from Congress to develop a system for gathering information from energy companies that could be used to determine national policies on energy production and regulation. A proposed reporting form was released June 22.

The GAO said that although "DOE obtained some suggestions and advice from various parties on data needs and uses, we have found no evidence to indicate that this information dictated the data in DOE's proposed collection form."

The reporting system should be designed only after the Energy Department has determined what policy uses will be made of the information, GAO said.

The accounting office also criticized aspects of the proposed reporting system relating to small energy producers, saying the Department of Energy has not yet designed its reporting forms for small producers and further delay could jeopardize the department's timetable for bringing small producers into the reporting system.

Depending on actions by other federal departments, the 29 largest energy companies could be involved in a financial reporting system by late this year, and small producers could be included by mid-1979.

The GAO also said the energy Department's plan to sample only small energy producers - rather than gather information from all companies - was not consistent with the legislation establishing a reporting system.

If the department thinks sampling is the best way to get information from small producers, then it should seek the necessary legislative changes, the GAO said.