Poland's youngest children returned to school on Monday for the first time in over two months but most pupils will remain in virtual classrooms as experts warned of a growing psychological toll.

Poland has seen some of the longest school closures in Europe due to Covid-19 but many parents are concerned that children may be returning too soon.

"I don't like the idea of children going back to school. I'm worried about my son," said Rafal Kazimierczak, 46, a sports journalist.

"He's only nine years old and too young to be demanded to adhere to a strict sanitary regime. It's impossible to maintain social distance."

Grades 1-3 are returning to school for the first time since November 9. Older primary schools, Grades 4-8, have been out of physical schools since October 26. Secondary schools and universities shut on October 19.

Psychologist Beata Trzesniewska said long periods away from the classroom were having a negative effect.

"Cases of depression among pupils and students are going up," she said.

Children and students "are saying they do not see the purpose of studying, have no interest in their current life, feel sad or bored or that nothing has meaning.

"Above all, they feel that they have no way of influencing what is happening right now," she told AFP.

The government has said it wants to bring more children back but is starting with the youngest as it says they are least likely to be infected and remote learning for them is least effective.

"We are of course striving to get children back to school as soon as possible, as safely and securely as possible for children, teachers and all school staff," President Andrzej Duda said on Friday.

Poland on Monday reported 3,271 new coronavirus cases and 52 additional deaths.

'Stop-start-pause' schooling

A ranking by the Insights for Education Foundation, a Switzerland-based non-governmental group, shows Polish schools have been closed for 128 days, putting it second in the EU after Romania with 140 days.

The list is stopped by Panama, Bolivia and El Salvador with 295, 270 and 267 days of closed schools.

Randa Grob-Zakhary, head of Insights for Education, said access to remote learning and the quality of that learning have been "very variable" around the world.

"The common assumption that school is dangerous has not held up. There are ways that countries have shown to safely and gradually return schools," she said.

"Poland is showing this by re-introducing Grades 1-3."

Grob-Zakhary said she believes there would be no "post-Covid period soon" and countries had to "help children flourish alongside Covid and stop this stop-start-pause" with school closures and re-openings.

Kazimierczak's partner Marta Mikiel, a 45-year-old PR agent, was sceptical that schools would stay open for long.

"It may all end in quite a short time with an increasing number of sick people," she said.