Four Polish lorry drivers have been arrested following the discovery on suspicion of facilitating illegal immigration, the BBC reported.
The 68 people were found inside four lorries at the dock. The ambulance service had earlier reported they were inside a locked container.
Thirty-five of the people were from Afghanistan, 22 were Chinese, 10 Vietnamese, and one Russian, Sky News reported.
Fifteen of the 68 were children.
Original story below:
Sixty-eight people have been discovered inside four lorries at Harwich International Port in Essex.
The East of England Ambulance Service said medical crews were sent to the scene after receiving a call shortly after 10pm on Thursday.
Seven of the 68 people, including the two pregnant women, were taken to Colchester General Hospital suffering from abdominal and chest pains, The Guardian reported.
The ambulance service said none of those treated were in a life-threatening or serious condition.
The remaining 61 were released to border agency officials.
Matthew Broad, a member of the ambulance service, said the people in the container were "mixed nationals from a number of countries, European and further afield", the BBC reported.
"We have experience of dealing with this in Essex, and one of the things we were concerned about was the length of time they'd been in there."
The lorries are believed to have come from Holland on Thursday, The Guardian reported.