I have a commercial property in a Canadian city which I have…

Yes. This is what the Occupational Health and Safety Act says: (it is long, but it gives you full information on their powers and your obligations)

Section 72:
For the purposes of enforcing and administering this Act or the regulations, an occupational health officer may do all or any of the following:
(a) subject to subsection (2), at any reasonable time of day or night and without prior notification, enter any premises, place of employment or vehicle where the officer has reason to believe that workers or self-employed persons work or have worked;
(b) make any inspection, investigation or inquiry that the officer considers necessary;
(c) require the use of any machinery, equipment, appliance or thing located at the place or premises to be demonstrated for the purposes of the inspection, investigation or inquiry;
(d) conduct any tests, take any samples and make any examinations that the officer considers necessary or advisable;
(e) take one or more persons to any place of employment to assist the officer and may make arrangements with the person in charge of the place of employment for those persons to re-enter the place of employment to perform specified duties;
(f) require the production of, inspect and take copies of any books, records or documents kept pursuant to this Act or the regulations or of any entry in those books, records or documents;
(f.1) require the production of, inspect and take copies of any existing records related to training workers on matters related to occupational health and safety;
(g) subject to subsection (3), remove any books, records or documents examined pursuant to this section for the purpose of making copies where a copy is not readily available, if a receipt is given;
(h) require any person whom the officer finds in or at a place of employment to provide the officer with any information the person can respecting the identity of the employer at that place of employment;
(i) subject to subsection (1.1), require any person who the occupational health officer has reasonable cause to believe possesses any information respecting a work related fatality, serious injury or allegation of harassment to attend an interview and provide full and correct answers to any questions that the officer believes it necessary to ask.
(1.1)
persons other than:
An interview held pursuant to clause (1)(i) is to be held in the absence of
(a) a person nominated to be present by the person being interviewed; and
(b) any other persons whom the occupational health officer may allow to be
present.
(2) An occupational health officer shall not enter a private dwelling without a warrant issued pursuant to subsection (4) unless the occupant of the dwelling consents to the entry.
(3) An occupational health officer who removes any books, records or documents pursuant to this section for the purpose of making copies shall:
(a) make those copies as soon as reasonably possible; and
(b) promptly return the books, records, papers or documents from which the
copies were made to:
(i) the place from which they were removed; or
(ii) any other place that may be agreed to by the officer and the person who produced them.


(4) A justice of the peace or a judge of the Provincial Court of Saskatchewan may issue a warrant authorizing an occupational health officer to enter and search any place or premises or search any vehicle named in the warrant where the officer believes, on reasonable and probable grounds, that:
(a) an offence against this Act has been or is being committed; and
(b) there is evidence of the offence to be found:
(i) at the place or premises proposed to be searched; or
(ii) in the vehicle proposed to be searched.
(5) An occupational health officer with a warrant issued pursuant to sub- section (4) may:
enter and search any place or premises named in the warrant; search any vehicle named in the warrant;
(c)
at the place or premises to be demonstrated for the purposes of the search; and
require the use of any machinery, equipment, appliance or thing located
(d) seize and remove from any place, premises or vehicle searched anything that may be evidence of an offence against this Act.
(6) An occupational health officer may exercise all or any of the powers mentioned in subsection (5) without a warrant issued pursuant to subsection (4) if:
(a) the conditions for obtaining a warrant exist; and
(b) the officer believes, on reasonable and probable grounds, that the delay
necessary to obtain a warrant would result in the loss or destruction of evidence.
(7) No person shall obstruct an occupational health officer who is authorized to conduct an inspection, investigation, inquiry or search pursuant to this section.

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