The incident allegedly took place at Carrickfergus harbor on the north shore of Belfast Lough.
It is understood that a merry-go-round at Planet Fun – a theme park open until mid-August – has collapsed.
Images from the scene show several emergency service vehicles present.
Do you know what happened? Send an e-mail to [email protected]
A statement from Planet Fun, posted on social media, said: “Important update. Please note that due to unforeseen circumstances Planet Fun will be closed tonight for the 7:30 pm-10:30pm session.
“All tickets will be automatically refunded. Further updates will follow. “
One woman said: “I was on the ride with all the children, one very badly injured, one in his ankle and one in shock. Absolutely terrifying will never return. “
But Stewart Dickson, Alliance MP for East Antrim, said “the first indications” are that the injuries “are not serious”.
He told BelfastLive he understood ambulances had been dispatched to the port car park.
Mr Dickson said: “I want to express my concern at this breaking news, I hope the early indications are that the injuries are not serious.
“I will expect a full investigation from the Health and Safety Agency and the local MEA council. “