A gigantic hammer that swings to a maximum height of 55m and a colourful 35m-tall neon-lit tower have risen up in Marina Bay.

The 55m-tall Mach 5 and the Star Flyer, a carousel in which riders' legs dangle as they spin round and round taking in the surrounding sights, are part of 22 rides and attractions at the Prudential Marina Bay Carnival.

The carnival, billed by event organisers as the biggest in Singapore, will open today and run until April 1.

It was supposed to start a week ago, but organisers were awaiting the final go-ahead.

Occupying an area the size of 3-1/2 football fields, the carnival is held at the Promontory and Bayfront event space.

Entry to the event is free, but there are charges for the rides and game booths, which have more than a million prizes, such as plushies from the Minions franchise.

Local musicians such as singer Tay Kexin and hip-hop rapper TheLionCityBoy will perform during the carnival.

Food such as chendol soft serve and lemongrass chicken rice bowls will also be on sale.

The opening hours are from 4pm to 11pm daily, except for Christmas Eve and New Year's Eve, when the carnival is open from 3pm to 2am.