The Canada Border Services Agency’s (CBSA) allows intellectual property rights holders to file a request asking for the CBSA to temporarily detain suspected counterfeit goods encountered at the border while rights holders seek legal redress. To request help from the CBSA, you must complete and submit a Request for Assistance (RFA) application (Here). There is no application fee, but you must be a rights holder of a valid Canadian copyright or your trademark must be registered with the Canadian Trademarks Office to apply. If suspected counterfeit and/or pirated goods are discovered by the CBSA, they will use the information contained in the RFA application to contact the appropriate rights holders/owners and inform them of the details they need to allow them to pursue a civil court action. For more information about how to file an RFA application, click here.

The Trade-marks Act contains the following general prohibition:

51.03 (1) Goods shall not be imported or exported if the goods or their labels or packaging bear – without the consent of the owner of a registered trade-mark for such goods – a trade-mark that is identical to, or that cannot be distinguished in its essential aspects from, that registered trade-mark.
This gives registered Canadian trademark owners the right to sue counterfeiters who pass off their goods as those of registered Canadian trademark owners in Canada even if the goods are:

(a) manufactured/labelled elsewhere and then attempted to be imported into Canada; or
(b) manufactured/labelled in Canada and then attempted to be exported to be sold elsewhere.
Under the Customs Act:

101 Goods that have been imported or are about to be exported may be detained by an officer until he is satisfied that the goods have been dealt with in accordance with this Act, and any other Act of Parliament that prohibits, controls or regulates the importation or exportation of goods, and any regulations made thereunder.
This authorizes officers to detain counterfeit goods for an indefinite period to be used as evidence for a civil court action or to simply be disposed of and taken out of the hands of the counterfeiters.