A mandatory quarantine measure will now stay in place until at least 31 August. People entering the country, including citizens returning home, must self-isolate for 14 days upon arrival.
The travel ban for most other foreign travellers is extended to at least 31 July. Both measures were previously set to expire on 30 June.
US citizens are covered under a separate agreement that was extended until 21 July in mid-May. The US-Canada border remains closed to all non-essential travel until then.
The country has harsh penalties for violating quarantine orders. An individual can be fined up to C$750,000 and be imprisoned for six months.
Canada has been largely successful in limiting the spread of the virus, but there are concerns about community spread in potential large gatherings to celebrate Canada Day on 1 July.
In a reminder to both Canadians and Americans, the Canada Border Services Agency reiterated its message that the border remains closed over both countries' national days in early July.
Canada has reduced the spread of Covid-19 to the point that it was included in the 'safe list' of countries travellers from which would be permitted to enter the European Union, also announced on Tuesday. The US, which has seen spikes in cases in southern and western states over the past weeks, was not included.
As in much of the northern hemisphere, when travel regulations were initially set up in the early days of the pandemic, it was hoped that cases of Covid-19 would have largely subsided by the summer in time for peak tourism season.
Canada closed its borders to non-essential foreign travellers who are not Canadian citizens, permanent residents or Americans in March. It is unclear when they will be reopened.
Limited exemptions to the border measures were made for immediate family reunification. Other exemptions are also in place for specific groups of individuals including diplomats, flight crews and those holding valid work or study permits.
As of 29 June, Canada had 103,918 cases of Covid-19 of which 67,178 cases had recovered. There have been 8,566 officially recorded deaths.
With reporting from Reuters