The fire department is expecting to see a spike in the number of arrests for fire-related crimes across the city following the opening of a new base for investigators, fire department officials said yesterday.

Forty-six members of the Bureau of Fire Investigation, a growing branch of the department, are now working out of the new 12,000-square-foot base that was opened last month at Fort Totten in Queens, fire officials said.

The new base, along with the creation of 32 new fire marshal positions in July, should allow investigators to probe roughly 1,400 more fires a year, officials said. Fire marshals investigated 6,023 fires in 2006.

A stouter investigation bureau will also lead to more arrests, officials said. Fire marshals and assisting law enforcement departments made 281 arrests in 2006. As of yesterday, 307 arrests had been made this year.

With the opening of the base at Fort Totten, the fire marshals are now able to run the bureau more efficiently by virtually splitting their operations in half, officials said.

Citywide South Command, based out of the bureau’s old headquarters in Brooklyn, is investigating fires in Brooklyn, Staten Island, and Manhattan south of 110th Street, while the north command at Fort Totten is in charge of investigations in Queens, the Bronx, and northern Manhattan, officials said.

“Fire marshals are an essential component in protecting the security of this city, and this new base will allow them to conduct more investigations efficiently,” Commissioner Nicholas Scoppetta said in a statement.

The new base and the creation of the new fire marshal positions are a result of $1.4 million included in Mayor Bloomberg’s budget for fiscal year 2008, fire officials said.