The University of Otago has a "two-stage" system for the safe management of contractors on site. Please note that "contractors" includes companies, sole traders, and consultants, not just individual employees:
Before being able to work on campus, contractors must be approved as health and safety compliant by the University’s Health & Safety team, which requires evidence of robust health and safety systems. Email email@example.com for more details.
Once a contractor has been approved, employees of that contractor (including sole traders and consultants) must complete a health and safety induction so they understand the University’s practical health and safety requirements. Once they have been inducted, employees will receive a University ID card to show that they can work on campus.
If any sub-contractors need to be employed, these sub-contractors must also be University-approved (and attend an induction) before commencing work on campus.