Three children in Sweden have been removed from home after their parents locked them up for four months fearing they might catch the coronavirus, the youngsters' lawyer said on Wednesday.

Between March and early July, the children, aged 10 to 17, and the family "were prohibited from leaving the apartment", lawyer Mikael Svegfors told AFP.

The children were not allowed to see each other, locked in their own rooms and ate their meals there, said the Jonkoping administrative court in southern Sweden.

In addition, the door to the home had been "nailed shut" so no one could go out, the court found.

The parents deny locking in the children against their will and plan to appeal the ruling, local radio reported.

Unlike many other European countries, Sweden did not impose a strict lockdown and kept schools open for children under 16. The Scandinavian country has one of the world's highest Covid-19 death tolls relative to population, with 575 deaths per million.

The parents "come from another part of the world" and do not speak Swedish fluently, lawyer Svegfors said.

"They couldn't really understand the news here. They kept following the news feed over internet from their old country" which had imposed much stricter confinement measures.