A five-year-old has died in Poland after eating poisonous mushrooms and his six-year-old brother remains in a life-threatening condition.

       Doctors at Poland's main children's hospital confirmed on Thursday that the boy, who had recently been evacuated from Kabul, had died.

       His six-year-old brother remains at the Centre for Children's Health Institute in Warsaw and has undergone a liver transplant.

       The two children and their older sister were hospitalised last week after consuming the mushrooms near where they were staying.

       It is understood that the family had collected highly poisonous death cap mushrooms in the forest around the refugee centre in Podkowa Lesna, near Warsaw.

       While the 17-year-old girl has been released in good condition, doctors said that the older brother had suffered significant damage to his brain.

       "His condition is similar to that of his younger brother two days ago," hospital director Marek Migdal told reporters. "Unfortunately, we were not able to help the two boys."

       The parents of the children were also at the hospital under psychological care.

       Poland had evacuated the family last month at the request of the United Kingdom after the Taliban takeover of Afghanistan.

       Jakub Dudziak, a spokesperson for the Foreigners' Office that runs migrant centres in Poland, has denied reports that the children had eaten the mushrooms because they were not sufficiently fed.

       In a separate incident, four Afghan men were also hospitalised after eating poisonous mushrooms near a different refugee centre in Warsaw, according to the office.

       "In connection with this unfortunate accident, employees of the centres will raise awareness among Afghan citizens not to consume products of unknown origin," Dudziak said.

       Poland completed its evacuation mission last week after removing 1,231 people from Kabul.