Finnish schoolchildren began returning to class on Thursday after eight weeks of coronavirus lockdown despite warnings from the teacher's union it may not be totally safe for its staff or the children.

The reopenings see pupils back at school for just over two weeks before the summer holidays begin in early June, with strict social distancing rules in place.

Break times will be staggered to avoid large numbers of children in the playground at once, and unused spaces will be turned into classrooms to allow pupils to spread out, Education Minister Li Andersson said when announcing the decision on 29 April.

On Tuesday, Andersson announced that laws were being drafted to allow for schools to switch between classroom and distance teaching as required once term starts again in mid-August, if the epidemic spikes.

Finland has so far recorded 284 coronavirus-related deaths and over 6,000 infections, a lower rate than neighbouring Nordic countries, which has led epidemiologists to warn that future waves of the virus may prove more serious.

The Finnish union of teachers criticised the plan to restart teaching in classrooms rather than remotely.

The union said in a statement that "it is not clear that this is in the interests of the children" and warned schools may not "be able to fully ensure safety for the children or staff."

The state's top epidemiologist, Mika Salminen, however defended the move, telling a press conference on April 29 that "the share of children with the disease is small."

"The risk of a child infecting an adult is not realistic. Opening schools is risk-free."

Opinion polls on Wednesday suggested the public was evenly split on the issue.

Finland introduced lockdown measures in mid-March which included the mandatory closure of schools for all children over 10, with younger children told to remain at home unless their parents were essential workers.

All children are now obliged to return to school unless they can produce a doctor's certificate authorising them to continue distance learning.

A survey by national broadcaster Yle claimed on Wednesday that around five percent of pupils, numbering 30,000, would be eligible to remain at home after Thursday.

In early May the government announced a plan to gradually lift lockdown measures, but restaurants, bars and cultural institutions such as theatres would only be allowed to open their doors on June 1, under social distancing rules and a ban on gatherings of more than 50 people.