Belgium's Haren prison is increasing capacity on an emergency basis by converting 43 single beds into bunk beds in 43 cells to add 43 places amid rising overcrowding.

The measure was approved over the weekend by the prison administration and is described as an emergency step by officials from the prison system and the Belgian federal justice ministry.

Until the plan is implemented, some prisoners at Haren are sleeping on mattresses on the floor, with more cases likely in the coming days.

Prison authorities warn that working and detention conditions are deteriorating and urge rapid action to relieve overcrowding.

Haren, once relatively spared, is now part of a nationwide overcrowding issue where Belgian prisons hold 13,459 inmates for a capacity of 11,098, leaving at least 525 inmates sleeping on mattresses on the floor across the country.