On Wednesday, tourists and locals hoping for a sky-high view of Singapore from the world's largest observation wheel were turned away as the Flyer stayed shut by order of the Singapore Police Force.

The Flyer requires a public entertainment licence to operate. As the licensing authority, the police said they will allow operations to resume only after the Flyer's structural and mechanical systems are certified safe by an internationally recognised body.

Police are also investigating whether any of the licensing conditions were breached, although at this time 'there is no evidence to suggest that the incident was deliberate'.

Working with the Singapore Civil Defence Force, the Flyer's management and independent experts, police investigations will look into how the problem occurred, how it can be prevented and what measures can put in place to enhance passenger safety.

Senior management from the Ministry of Home Affairs will oversee the investigations, said the police statement.

It added: 'It is premature at this stage to say how long this process will take.'

The Flyer's general manager Steven Yeo added: 'At this point in time, we are not able to tell you but it is unlikely to be ready by New Year.'

Flyer officials and engineers from the builders Mitsubishi Heavy Industries were on the scene looking into how a fire in the control room on the third floor of the complex led to a short-circuit that brought the wheel to a grinding halt.

One question many passengers had was whether winching them down to the ground was the best way to rescue them. In Britain, the London Eye is designed such that it can be turned manually by staff, even if the back-up power fails.

Mr Yeo said the bigger Flyer is not designed for such movement.