Dozens of Canada's most prominent chief executives are putting competitive instincts aside and urging all leaders to immediately embrace social distancing to arrest the rapidly-spreading COVID-19 outbreak.

"While this will have significant economic impact on our businesses in the short term, it is critical to weathering this storm and hasten the recovery," reads the letter.

As of 11:30 p.m. ET Sunday, signatories included the heads of Canada's Big Six banks, major pension plans, including the Canada Pension Plan Investment Board and Caisse de dépôt et placement du Québec, as well as insurance conglomerates Manulife Financial Corp. and Sun Life Financial Inc., among many others.

Canada's official tally of confirmed cases was 304 as of 5:45 p.m. ET Sunday, in addition to 17 probable cases. Chief Public Health Officer Theresa Tam warned of the immediate need to flatten the curve of growth in this country and said "the time for all Canadians to act is now." 

In their open letter, the Canadian chief executives called on leaders to encourage their employees to halt all non-essential travel and enable social distancing by adopting work-from-home policies for all non-critical functions.

They also encouraged continuity in essential services by coordinating with governments, and made it clear leadership was crucial as fears about the virus intensify.

"Understand that your employees are looking to you for leadership and trusted information in turbulent times," they wrote.