Emergency services were called to the Port of Dover after reports of people found on board a vessel.
The ambulance service and police are supporting the Border Force after the discovery on Sunday.
A spokesman for the South East Coast Ambulance said they were called late yesterday evening to support Border Force with “an incident at Dover Western Docks”.
They sent an ambulance team to attend and they remain on the scene.
This morning, emergency services including specialist paramedics and a fire service vehicle remained in attendance along the pier.
A spokesman for Kent Police said: “Kent Police officers are currently assisting Border Force colleagues in Dover after a number of suspected migrants were found on board a vessel.”
The Home Office has been approached for comment.
Read more: All the latest news from Dover