The incident took place late last night in Waraq area near here, Interior Ministry said in a statement.
Following the collision, the passenger boat sustained damage, causing it to sink in the river. Six people have been rescued and the captain of the cargo boat has been arrested, the ministry said.
At least 18 divers and eight rescue boats are searching for survivors after it was estimated that around 25 people were on board the ferry when it met with the accident, it added.