A 12-minute pyrotechnic display of colour and light over Sydney Harbour ushered in the New Year at midnight, kicking off a string of celebrations for billions across the world.

More than 1.5 million people amassed over the biggest Australian city to witness shapes of clouds and hearts in the skies.

'Every year we make sure our celebrations are bigger and better than the one before,' Sydney Lord Mayor Clover Moore was quoted as saying by agencies.

The festivities to welcome the new year will run from Hong Kong’s bustling harbour and Berlin's Brandenburg Gate to London’s River Thames and New York’s Times Square.