Mayor Ray Nagin's administration has quietly resumed an effort to raze about 1,500 flood-wrecked houses in New Orleans, directing its new demolition contractor this week to carry out as many as a dozen teardowns a day and to complete the task by August.

The demolition program was suspended in September, when monitoring of the work shifted from federal officials to City Hall and a new search for contractors was launched.

The federally financed initiative targets mostly houses classified as threats to public "health, safety and welfare" under an ordinance adopted last year, which gives the mayor's office broad powers to tear down buildings left virtually untouched since the flood. In addition to the so-called "imminent health threat" properties, the city also will focus on structures in danger of collapse, a Nagin spokesman said.

While the demolition program seeks to remove buildings that threaten overall neighborhood quality, the Nagin administration has drawn criticism from some housing advocates who say city officials haven't properly notified some of the affected owners. The advocates say the city should not have resumed demolitions without first fixing problems with the notification system.

Properties designated as health threats or in danger of collapse made up the bulk of roughly 4,300 buildings that were demolished after Hurricane Katrina by contractors for the Army Corps of Engineers. Until Sept. 30, the corps oversaw the removal of condemned, flood-damaged structures in New Orleans, as well as "voluntary" demolitions requested by homeowners. The corps was paid directly by the Federal Emergency Management Agency for the work.

Since then, City Hall-initiated demolitions for the most part have been suspended as officials solicited proposals from private vendors to take over the job, with the task covered by several contracts. With the two biggest contracts now in place - a $29.2 million deal with DRC Emergency Services of Mobile, Ala., for residential teardowns, and an $11.1 million management contract with Beck Disaster Recovery of Seattle - the work resumed in earnest in early February, Sanitation Director Veronica White wrote by e-mail this week.

"The city has reached its goal of completing at least 30 demolitions per week and will continue to strive for closer to 50 demolitions per week, weather permitting," White said.

As of Wednesday, 157 houses had been torn down, the vast majority of them condemned as health threats, Nagin spokesman James Ross said.

While firms handling the razing are dealing directly with City Hall, FEMA has committed to paying the full cost of their contracts through the storm's third anniversary on Aug. 29. The payments will be made through the Public Assistance program, which provides money for restoring damaged assets, from library books to public buses to bridges.

In all, FEMA has earmarked $51.8 million for the remaining New Orleans demolitions, of which the city has drawn down $11.3 million so far, according to a document provided by FEMA. Aside from the two main contracts, money has been set aside for three additional contracts that Ross said have not yet been awarded. They will cover demolition of commercial buildings, removal of household hazardous waste and selective removal of important architectural details from homes that face the wrecking ball.