The Bahamas government, citing security considerations, has expelled deposed Nicaraguan president Anastasio Somoza.

Somoza left Nassau yesterday abroad a U.S.-registered Convair 880 aircraft. His present whereabouts are unknown, although sources in Nassau say the plane arrived from Guatemala to pick him up and filed a return flight plan for Guatemala City.

Official sources in Guatemala said they had no knowledge of Somoza's arrival in that Central American country. A more likely destination was believed to be somewhere in the United States. Somoza's wife, Hope, is an American citizen and Somoza has a U.S. visa that is valid until 1983.

Somoza fled Nicaragua for Miami July 17. The deposed president and a party of family and friends sailed three days later from Forth Lauderdale for the Bahamas abroad two chartered yachts.

Bahamian officials at the time expressed concern about the security problems Somoza's presence would create and refused his request for a three-month visa. The Guatemalan government also is said to have rejected his request for a visa at about the same time.

As a Nicaraguan citizen, however, Somoza was eligible to enter the Bahamas and remain for 14 days without a visa.

He and his party arrived July 24 at Georgetown, Great Exuma, to the southeast of Nassau's New Providence Island. Once there, reports reaching Bahamian authorities in Nassau indicated that Somoza was contemplating an extended stay.

"we felt this was inconsistent with the position expressed by the government," an official said today. The government previously was embarrased by the stay of the deposed shah of Iran, who like Somoza was the focus of criticism in the opposition Nassau press. CAPTION: Picture, ANASTASIO SOMOZA problems cited in Nassau