Ontario Premier Doug Ford says the move to online-only will happen after the April break this week.

Schools in Canada's largest city, Toronto, were already shut on Wednesday. It and the neighbouring Peel region decided to act after the province declined to.

Ontario is seeing more than 4000 new infections daily, including 4401 on Monday, and record intensive care numbers.

Spring break began on Monday after the province postponed it in March to discourage travel.

"Bringing our kids back to a congregate setting in schools after a week off in the community is a risk I won't take," Ford said.

Education Minister Stephen Lecce said the government will rely on the advice of the chief medical officer of Ontario to determine when schools will resume for in class learning.

On Sunday, Lecce said schools would re-open for in class learning next week. Opposition Liberal leader Steven Del Ducca said Lecce should be fired.

Ford has been criticised by health officials for not doing more to get infections under control after months of warnings.

"I can't stress this enough. We are at a critical point right now. Many of the health indicators continue to surpass the worse case scenario," Ford said.

"I'm extremely concerned about the new variants."

Vaccinations have ramped up in Canada in recent weeks and all adults who want a vaccine are expected to get at least one dose by July.

Canada has lagged in vaccinations because, like many other countries, it lacks the ability to manufacture vaccines and has had to rely on the global supply chain.

While hope is on the way with more than 45 million doses expected to be available by July for the nation of 38 million people, cases in Canada are surging.

The Ontario Hospital Association said nearly all hospitals in the greater Toronto area would close their pediatric units to help accommodate a surge in COVID-19 cases.

Toronto's chief medical officer of health said the city could see 2500 daily new COVID-19 cases by the end of April, even with a stay-at-home order in effect.

"When the Hospital for Sick Children is providing ICU care for adults you know you are living in one of the worst periods of the pandemic," said Dr. Eileen de Villa, the city's medical officer.

Canada's chief public health officer, Dr. Theresa Tam, said there are more than 33,000 confirmed cases involving contagious variants in Canada.

Most still involve the B.1.1.7 variant first detected in the United Kingdom but there has also been a "concerning rise" in the number of cases of the P.1 variant, first associated with Brazil.

Australian Associated Press