"We urge the Saudi authorities to immediately release them and all other peaceful human rights activists".
On Monday, Saudi's foreign ministry recalled its ambassador to Canada for consultations and declared the Canadian ambassador persona non grata, giving him 24 hours to leave.
Dan McTeague, a senior analyst at the fuel price tracking website GasBuddy, said any such disruption could easily be offset by alternative supply, as Saudi Arabia's oil continues to represent an increasingly small portion of Canada's crude imports.
The dispute appears to have been sparked by tweets from Canadian diplomats, including one from Canadian Foreign Minister Chrystia Freeland, who said she was "very alarmed" by news of the arrest of Samar Badawi, the sister of prominent activist and writer Raif Badawi.
Media captionSaudi Arabia's permanent representative to the United Nations confirmed the change in policy What has the relationship between Saudi Arabia and Canada been like in the past?
Since Monday social media has been saturated by the surprising news that Saudi Arabia chose to expel the Canadian ambassador, along with freezing trade and investment ties with Canada.
The news comes just weeks before thousands of Canadians are expected to travel to Saudi Arabia to perform Hajj.
Travel to the country will affected in light of an announcement from Saudia Airlines on Tuesday that it will suspend flights to and from Canada starting August 13.More news: Chelsea 'leading' Zaha race
Meanwhile, through a statement published by the Palestinian Press Agency, President Mahmoud Abbas also assured the support of Palestinians to Saudi Arabia and its move against Canada's intervention.
"We're going to stand with the values that we know are important to Canadians and Saudi Arabia will take the decisions that they take", Morneau said. His wife, Ensaf Haidar, lives in Canada and recently became a Canadian citizen.
Samar was arrested along with fellow campaigner Nassima al-Sadah last week, the latest victims of what Human Rights Watch called an "unprecedented government crackdown on the women's rights movement".
In the statement, the ministry said, "Oman is following the current political situation between Saudi Arabia and Canada and affirms its position of not interfering in the internal affairs of other countries".
But Riyadh's singling out of Canada is aimed at strongly discouraging other critical Western governments from speaking out, observers say.
"So neither Saudi nor Canada are going to be affected much by stopping the wheat and barley trade".
"We are waiting to hear from Saudi Arabia details of its response and we look forward to hearing those details".