BUCHAREST, Romania (AP) _ The Communist Party dismissed three deputy premiers from the 64-member Cabinet in this month's second reshuffle of key economic posts, the party daily Scinteia said Saturday.

The party's executive political committee added two deputy premiers at its meeting Friday, the daily said. It said the changes were ''to strengthen the management of activity of some sectors and economic ministries.''

President and Communist Party chief Nicolae Ceausescu presided over the meeting, it said.

On Sept. 3, the committee restructured key economic departments and pinpointed shortfalls in fulfilling plan targets. It requested ''firm measures for the radical improvement of the entire activity.''

Vital sectors such as coal, oil and chemical production have been behind targets in recent years and serious energy shortages over the past three winters have led to stringent conservation measures.

On Friday, Dimitrie Ancuta, Ion C. Petre and Aneta Spornic were relieved as deputy premiers to be given other tasks, the party daily said.

Stefan Andrei, a senior party offical, and Ion Constantinescu were named deputy premiers overseeing economic activities, it said.

Constantinescu was relieved of his post as ministry state secretary at the State Planning Committee, but no mention was made of who would take over that post.

Andrei, 56, served as foreign minister from 1978 to 1985, when he was appointed a party secretary responsible for economic problems.