The Conference Board says the forward-looking help-wanted index shrunk by 9.5 percentage points in June, which suggests the economy could have shed about 10,000 workers in July.
All the provincial indexes registered a decline, with the exception of New Brunswick, the think-tank says.
After a stunning 95,000 job gain in May, economists had expected some payback the following months and were pleasantly surprised when June's loss was limited to only 400 workers.
Analysts are expecting more weakness in next week's report from Statistics Canada, with the early consensus pointing to a 6,000 pick-up.
Friday's release from Washington pointed to a soft employment landscape in the U.S. as well, with July showing a below-consensus 162,000 gain and downward revisions for both June and May.