No, the OHSACT does not stipulate that you must have an agreement in place at all. In fact, this is the only piece of legislation that indicates that the employer “is guilty until proven innocent” unless an employer can prove, they applied the “duty of care” and specific requirements being adhered to. This is based on the premise of vicarious liability in that whatever the employees and or contractors do, or not do, the employer remains liable for the actions, unless an agreement has been reached whereby the employer is indemnified if he can prove he fulfilled his obligations entirely.
It is therefore not a specific requirement to have an 37(2) agreement in place however it is deemed good practice, unless the employer feels he can fairly manage a contractor’s activities in addition to his own business activities. For more information on this topic please read the article
“What is Section 37(2) and Why is it Important for Workplace Safety?”