The issue came up when four Alberta fathers challenged  retroactive court orders.

Dedre Smith, who represented the men, says its going to be a challenge for the courts.

"The next few months, while we set up the administrative system will see a few hiccups but in about 18 months systems should be in place."

She says the supreme court expects some 700-thousand families will be adjusting their support annually.

And it will cause some problems for the judicial system because they do not have the administrative systems in place to make it happen.