TOKYO (AP) _ Prime Minister Yoshiro Mori's Cabinet resigned en masse Tuesday morning, formally opening the way for Mori to announce a new Cabinet that will oversee a sweeping restructuring of Japan's bureaucracy.

The resignations, a formality before the changes, were submitted at the regular morning Cabinet meeting, said Kazuhiko Koshikawa, one of Mori's spokesmen.

Mori, one of Japan's most unpopular prime ministers in years, was expected to announce the new Cabinet as early as Tuesday evening. He hopes the change will breathe new life into his sagging administration.

The reshuffle was not expected to be a major one, as Mori had said he will stress continuity in his selection of new ministers. Foreign Minister Yohei Kono and Finance Minister Kiichi Miyazawa _ the two most prominent ministers _ were both expected to retain their positions.

Recent public opinion polls put support for Mori, who assumed office in April, at under 20 percent. He just barely survived a rebellion within his own party to beat a no-confidence motion two weeks ago.

Mori's new Cabinet was expected to face some difficult months ahead.

Figures released this week showed that although the nation's economy is expanding, it is still not clearly on the road to recovery after its worst slowdown in decades. Concerns have been raised that Mori, whose support within his Liberal Democratic Party is shaky, is not strong enough to push for any tough economic measures.

His new Cabinet will also have to deal with the new bureaucratic framework initiated to make Japan's government less cumbersome and more responsive to the nation's needs.

To reflect the bureaucratic reforms, Mori is naming a smaller Cabinet. The current 22 ministers will be reduced to at most 17, with many of the former posts combined and other new positions created.