WINNIPEG -- The union for Manitoba's social workers says the government was warned long ago that child welfare in the province was so overwhelmed that children were in danger.

The Manitoba Government and General Employees Union on Friday released three letters it wrote to the government between 2002 and 2005. They warned of skyrocketing caseloads and stressed-out workers at Winnipeg Child and Family Services.

Social workers have faced criticism at a public inquiry into the 2005 death of Phoenix Sinclair, who was in and out of foster care and fell through the cracks of child welfare.

"We really feel that the public -- everyone actually -- is drawing conclusions about the work these people did," said Janet Kehler, a union staff representative and former social worker.

"To really understand the work they did -- or didn't do as the case may be -- you really need the context that they were doing the work in."

One letter, written by the union to then-family services minister Drew Caldwell in December 2002, warned that the number of children in care in Winnipeg had risen sharply and many frontline workers were quitting because they were so overwhelmed.

"It is for the above reasons that we feel we must put this government on notice that children and families who require protection services in Winnipeg are at risk and we as workers feel unable to ensure their safety," the letter said.

Another letter, written in 2005 to then-minister Christine Melnick, warned that the government's move to transfer cases to aboriginal-run agencies was creating chaos.

"Clients are confused, upset and angry, not knowing who their new worker is and where that worker may be located."

The union's decision to release the letters followed weeks of inquiry testimony that has revealed social workers at the Winnipeg agency failed to keep track of Phoenix for months at a time and failed to provide proper support for her troubled parents.

Phoenix spent her life bouncing among foster care, the homes of her separated parents and the house of a family friend. Months after social workers returned the child to her mother, Samantha Kematch, the girl was beaten to death by Kematch and her boyfriend, who horribly abused Phoenix before she died at the age of five. Her death went undetected for nine months.

The inquiry is still in its early stages, but has already heard of big gaps in Phoenix's care. A few months after her birth, her parents were supposed to have weekly visits with a social worker and receive in-home support. That didn't happen.

In early 2003, following a nose infection that required Phoenix to be treated in hospital, a social worker was supposed to inspect the girl's living conditions but never managed to find anyone at home.

In the summer of 2003, Phoenix's father, Steve Sinclair, was regaining custody of Phoenix and was supposed to get alcohol counselling first. He didn't, but was awarded care of the girl anyway.

An internal review of the case in 2006 by Winnipeg Child and Family Services but only made public last month said: "From October of 2000 to the last contact with this family, actual service was almost non-existent."

The most recent criticism has come from Rohan Stephenson, a family friend who cared for Phoenix during much of her life. He testified Thursday that social workers knew little about how Phoenix was being cared for. He called them "incompetent."

Kehler said social workers were trying to do their jobs under difficult circumstances. She suggested all the people involved with Phoenix are probably re-examining their actions.

"With the benefit of hindsight, would some people wish desperately they had made different decisions? Absolutely," Kehler said.

"I would say that's true for the social workers, for the community members, for the family, for the doctors, for the public health nurses -- for everybody who touched this case."

Family Services Minister Jennifer Howard was not available for comment Friday. She has previously pointed to investments the government has made in child welfare since 2006. The province has added 280 workers and has helped fund 5,000 new foster care and emergency shelter spaces. It has also changed the law to ensure that the protection of children is given priority over family reunification.

But the system continues to be challenged. Over the past decade, the number of children in care has almost doubled to more than 9,400.

"The socio-economic circumstances that social workers are dealing with have become increasingly ... complex and the demand for service has increased," Kehler said.

"Our workers are saying there's been no meaningful change in their ability to do the work in the way that they feel it ought to be done."

The lack of oversight in Phoenix's case is not the only criticism the union has faced. While it still has letters to government from the period when the girl was alive, the inquiry has learned that some notes taken by the supervisors of her case workers have been shredded.

The union was also the subject of public criticism when it tried to restrict the inquiry on two fronts. It filed a court motion to quash the hearings altogether, saying the death would be better suited to an inquest, which has a more limited scope and does not assign blame. The union also tried to get a court order protecting the identity of social workers who testify.

The courts rejected both attempts.