Katelynn Sampson, 7, was murdered by her legal guardian in 2008. (CBC)

Changes to how Ontario courts handle child custody cases came into effect March 1, reforms the government says will provide better protection for children.

The move came about, in large part, as a result of the killing of seven-year-old Katelynn Sampson in the summer of 2008.

The child's legal guardian, Donna Irving, was convicted of the murder, along with her boyfriend, Warren Johnson.

A family court judge had granted Irving custody two months earlier without asking about Irving's criminal record.

Now, judges in Ontario must consider record checks and Children's Aid Society reports before giving custody.

The reforms are being welcomed by people who work in child protection.

"I think it's the right move," said Karyn Kennedy, who runs Boost, a child abuse prevention agency in Toronto. "The courts have a responsibility to ensure that children are safe wherever they're placed."

Ella Bernhard, the executive of the Ontario Bar Association's family law section, supports the reforms, but is concerned they turn the judge from an impartial finder of fact into an advocate.

"If no one bothers to introduce criminal records, do you believe it's the obligation of the judge to call upon the party to complete or finish their case? I don't."