Auditor-General Karen Hogan is critical of the way employers treated temporary farm workers.
In her report presented to Parliament this week, she said they were not adequately protected from COVID-19.
Employment and Social Development Canada was in charge of inspecting their housing, but Hogan found inspectors granted approvals without conducting proper investigations.
The Migrant Workers Alliance for Change, which has been criticizing the way temporary farm workers are treated for years, said it knows of six who died of COVID-19, but believes it was more.
There are about 50,000 migrant farm workers in Canada every year.
Farmers say they are essential to their business.
They have invested in significant housing improvements and safety protocols and equipment, aided by a number of rounds of federal and provincial government funding.
