One of New York’s largest foster care agencies sued the city today in hopes of reinstating its contract to provide services to some 1,400 children.

Little Flower Children and Family Services’s contract had been terminated last month, after the agency was rejected under a new contract award process, instituted by the city, that the lawsuit calls “deeply flawed” and confusing.

Moving 1,400 children and their foster parents to different agencies will delay reunification with birth families by an average 4.4 years, and adoptions by 2.6 years, Little Flower officials insisted yesterday.

“Every time there’s another change it’s seen as another rejection,” foster mother Antoinette Cotman said of the prospect of her 12-year-old foster daughter getting used to new caseworkers, therapists and doctors.

The city’s Administration for Children’s Services stands by its new “procurement process, which is fair and objective,” city lawyer Terri Sasanow said in response to the Manhattan Supreme Court lawsuit, which asks a judge to vacate the new process.

And Mayor Bloomberg, asked about Little Flower today, insinuated that the 80-year-old foster agency simply wasn’t up to snuff.

“When we have services that don’t work we’re going to move monies from those services or those organizations that either aren’t patronized or aren’t used well or aren’t doing a good job, and we’ll go to those that do,” the mayor said.