WASHINGTON (AP) _ Scores of aviation near-collision reports were discussed at top-level Federal Aviation Administration daily briefings last year but never were included in the agency's statistics, ABC News reported Tuesday night.

The network said it obtained copies of daily briefing reports given to FAA Administrator Donald Engen in 1984 in which near-collision incidents were discussed. It said at least 136 of those incidents never were included in the agency's statistical tabulation.

The FAA acknowledged earlier this month that for years it had significantly under-reported the number of incidents in which two aircraft came dangerously close to one another. During 1983 and 1984 at least 352 such reports never were included in the national statistics, the agency said.

Engen at a news conference June 7 blamed ''some cracks in our (reporting) system'' and said the reports ''dropped into little pockets'' of the agency's bureaucracy and disappeared. FAA officials implied that most of the time regional offices did not report the incidents to Washington headquarters.

The ABC News report did not suggest the existence of any additional missing reports. But it said the daily briefings for Engen show that many of the ''missing'' reports actually were forwarded to Washington and discussed at the highest levels of the agency.

FAA spokesman Edmund Pinto, responding to the ABC News report, said the network was confusing different reporting systems.

The daily briefing reports are intended for Engen and other top-level FAA officials to get ''a snapshot'' of the air traffic control system on any particular day and was based on informal information telephoned to FAA headquarters during the night.

''The system was not devised as a means of counting near mid-air collisions,'' said Pinto. Statisticians tabulating near collision reports used a more formal procedure in which reports were sent to Washington in writing, he said.

Pinto said he could not confirm whether incidents referred to in Engen's daily briefings later failed to show up in the formal record keeping. But he said the two reporting procedures were distinctly separate and conceivably an incident discussed in the daily reports later might have not been forwarded formally to Washington.