The launch of a giant ferris wheel in Malacca went sour when a power cut trapped dozens of people on the inaugural ride.

Some 50 passengers including tearful children and an eight-month-pregnant woman were stuck 25 metres above the ground in the pitch dark on Saturday until rescuers managed to bring the gondolas down manually half an hour later.

The New Straits Times said the incident happened just as Malacca's state governor and chief minister arrived for their turn on the new RM3.3 million tourist attraction built on the banks of the Malacca River.

"I was shaken. This is a sign of poor safety features. I feel the ferris wheel is not ready for operations yet," Ibrahim Mohamed, whose daughter and grandchildren were trapped on the ride, told the daily.