Full details of the border closure with the USA were still being worked out but should come in a day or so, he said.
Trudeau added that his government would also provide C$55 billion additional aid to businesses and households through tax deferrals.
Finance Minister Bill Morneau said the government is encouraging every Canadian who can stay at home to do so, but acknowledged the wide-scale shut down of everything from schools to retailers to global travel, "is having a significant impact on our economy".
Deputy Prime Minister Chrystia Freeland described it as a "negative-list approach" - identifying travellers who should not be allowed to cross, rather than those who should - as she urged Canadians and Americans alike to take a breath and give the new bilateral agreement a chance to take effect.
The move builds on the United States president's barring of visitors from most of Europe, China and other parts of the world as the number of coronavirus cases in the USA surged past 9,400, with 150 deaths. On Tuesday, the European Union announced a 30-day ban on most nonessential travel to its 27 member nations, limiting it to food and medicine deliveries and people traveling to their home countries.
Trump said Wednesday that under the agreement, "trade will not be affected", but he did not specify any other details. "Our governments recognize that it is critical we preserve supply chains between both countries", Trudeau said.
Extra travel right now, based on government guidance, could be a hindrance to public health in stopping the spread of the virus.
Freeland pleaded for "patience and understanding" as she acknowledged that the government's agreement with the USA has been rushed into place, given the life-threatening urgency required in curbing the spread of the deadly COVID-19 illness. It's important for the border to remain open, considering the $2 billion worth of goods that cross it each day.
While it's still a bit too early to start calling it a regular daily appearance, Prime Minister Justin Trudeau will once again emerge from self isolation at Rideau Cottage to deliver an in-person update to Canadians on the latest developments in what his office continues to describe as "the COVID-19 situation". How will it be enforced?
"We are shocked that the government of Canada is not prepared to live up to that commitment".
When asked how soon the medical equipment could be ready, Trudeau answered, "soon".
"This is a temporary measure which we'll put in place for as long as the coronavirus crisis lasts".