The smoke from the fireworks above Marina Bay took minutes to clear, but the trash left behind by revellers took hours.

Close to 300 cleaners hired by the New Year countdown event organisers toiled from midnight until 7am yesterday to clean up the Marina Bay area, said the Esplanade's head of programme management (music and planning), Mr Joseph Tan.

They were deployed all around the bay, where massive crowds had gathered on New Year's Eve to watch the annual fireworks.

One cleaner, who wanted to be known only as Madam Tan, said the trash situation was not as bad this year, thanks to civic-minded partygoers.

She said in Mandarin: "I could see that many people held on to their trash as they left. Some thanked me and wished me a happy new year when they saw me."

The Marina Bay Singapore Countdown, jointly organised by the Urban Redevelopment Authority and the Esplanade - Theatres on the Bay, was Singapore's largest party of the night.

More than 300,000 revellers started heading for the exit as soon as the final fireworks display ended at 12.15am.

Most reached for nearby bins, though some chose to leave their empty cans, unwanted picnic mats and advertisement fliers behind. Many bins were overflowing with rubbish and revellers took to stacking cans and trash next to the bins.

Some 260 volunteers from the Lions Club of Singapore Mandarin stayed behind to help the cleaners until around 1.30am.

Donning signs that encouraged revellers to "bin it right", they had been handing out free garbage bags and fans throughout the evening as the crowd waited for midnight.

This was a first-time initiative at a New Year countdown event by the Public Hygiene Council as part of its Keep Singapore Clean Movement, said a spokesman for the council.

"Overall, the Marina Bay area was not really clean as we observed many pockets of littering. Our volunteers went around reminding members of the public to bag their trash and bin it," he added.

The crowd had mostly thinned by 2am, with the help of police officers and crowd marshals.

Said American tourist Ann Kemper, 29: "Even though it was awfully crowded, I love how everything was so well run. I can't imagine the party at Times Square (in New York) being like this."

The 12th edition of the countdown boasted several firsts, including the use of fire displays around the bay.

The celebrations were also extended to the Civic District for the first time to make space for activities, with St Andrew's Road and Connaught Drive converted to pedestrianised streets.

Mr Jonathan Yew, 54, who was at the countdown with his family, said: "This is a yearly tradition for us, to put the old year behind and welcome the new.

"2016 has been a happening year for many and you can see that everyone here is looking forward to a new start in 2017."