One year after federal agents detained more than 300 illegal immigrants at a New Bedford factory, advocacy groups continue to decry the “needless havoc” and lasting emotional fallout for detainees and their families, particularly children who were separated from their mothers.

One advocate calls March 6, 2007, “a day that destroyed the immigrant family” and sent reverberations throughout the country.

But a government spokesman says the raid succeeded as an “eye-opener” for employers who hire illegal immigrants, and as a deterrent to illegal immigration.

Meanwhile, a criminal case against the owner and top managers of Michael Bianco Inc., for allegedly hiring illegal immigrants to help fulfill military contracts, is moving slowly through federal court.

And volunteer lawyers representing some of the 361 original detainees say between 150 and 180 legal cases are proceeding, including numerous petitions for legal asylum. Paula Grenier, spokeswoman for the Boston office of Immigration and Customs Enforcement, said 35 detainees were released shortly after the raid on humanitarian grounds; 153 detainees were deported. One detainee remains in custody.

Some $200,000 has been raised through a New Bedford Immigrant Families/Ninos Fund for families affected by the raid, most of it going for food, shelter and clothing. Today, immigrant advocacy groups plan to mark the one-year anniversary in New Bedford.

“What happened here is that 361 people who were making backpacks for the armed services — their lives are destroyed because of an immigration system that ignores reality,” said Ali Noorani, executive director of the Massachusetts Immigrant & Refugee Advocacy Coalition.

“Since that day immigrant families across the country literally live in fear,” said Noorani. “This disregard for the safety or the sanctity of the family struck a chord in the country,” and organizations across the country “have taken steps to prepare themselves and their communities for a raid like the one that happened in New Bedford.”

Noorani said since the raid, MIRA has been “building on the public support because of this tragedy, to push for immigration reform.”

Bruce M. Foucart, special agent in charge for ICE’s investigations office in Boston, said the raid had positive effects nationwide.

“Do I think it was successful? Yes I do,” Foucart said. “What we’re trying to do, not only in New England but all over the country, is to stop the magnet, by preventing people who are hiring illegall aliens” from doing so. “Essentially, those employers are a magnet,” said Foucart, “and without those people hiring illegal aliens, there’s no incentive for them to come into the United States.”

Foucart said that the raid has prompted employers around the country to seek ICE assistance on verifying workers’ legal status.

He acknowledged that there has been “some longevity” in the criminal case against Bianco company owner Francesco Insolia and his managers, but said, “I think we have a very good criminal case that eventually will be litigated, hopefully in the near future.”

Foucart said he believes the widespread criticism of the raid is unjustified, and ICE “took unprecedented steps, beforehand, during and after the raid to ensure no children went without having a primary caregiver to go home to.”

Foucart acknowledged that the raid separated some children from their parents, “but my answer to that is, it lies solely on the parents.”

“When they entered the United States, they did so knowing they were breaking the law,” said Foucart. “They did so knowing they were going to be in this country illegally. They’re the ones who put their children in these positions ... ”

Foucart underscored the fact that “almost one quarter of the administrative arrests that we made were people who were already fugitives from U.S. immigration courts — either they had been deported and returned, or had existing warrants of deportation.”

Ondine Sniffin, a lawyer for Catholic Charities in New Bedford, is representing two dozen Bianco workers detained during the raid, most of whom are seeking political asylum. Greater Boston Legal Services is representing nearly all the others, Sniffin said. Lawyers for the agency could not be reached yesterday for comment.

Sniffin said most of her clients are seeking asylum based on fear of “gang-related persecution” if they return to their home countries, primarily El Salvador and Guatemala. “There may be links,” she explained. “If they had family members — either members of military or members of the guerrillas — and those families were persecuted in the past, the argument from an attorney’s perspective is that these second-generation continue to be persecuted.”

Corrine Williams, of the community Economic Development Center of Southeastern Massachusetts, said many children and families “are still living with the trauma of being separated” from one another after the raid, but those detainees remaining here “are continuing to fight on with their cases. Maybe it’s not what ICE expected would be the outcome. They might have had the expectation they could take all these people off the street and send them back to their home countries, but it turned out to be a little more complicated.”

Williams added, “I really question the wisdom of the large-scale raids. It doesn’t seem to be addressing what we need to address in terms of large-scale immigration reform. It leaves you with a feeling of so much disruption, so much trauma inflicted on these folks, and not a whole lot of resolution in terms of policy, which is on the downside, I think.”

kziner@projo.com