New Year's Eve celebrations around the world are now well and truly underway, with festivities already going strong in the south Pacific and Australasia. Extra security is accompanying the partying in many locations, but appears unlikely to dampen spirits.

Sydney has been welcoming in 2017 with its customary extravagant fireworks display over the city's famous harbour. However, like many other countries, the Australian celebrations also feature heightened security, following recent terror attacks in Berlin and Nice.

An additional 2,000 police officers were drafted in to the city and buses were be used to shut off some pedestrian areas to guard against a repeat of the terrorist atrocities in Nice and Berlin.

Nevertheless, around 1.5m spectators were estimated to have been present at the show, with seven tonnes of fireworks to provide the entertainment.

The show's schedule includes a "Willy Wonka" segment, in memory of the late actor Gene Wilder's most well-known role.

There are also tributes to David Bowie and Prince, both of whom died in 2016.

Earlier in the evening, a smaller display was mounted for families with young children who could not attend the night-time show.

As ever, the first nations to celebrate the New Year have been the islands of Tonga and Samoa in the South Pacific. Their fireworks started at 10am UK time. Next off was Auckland in New Zealand, which began partying an hour later. A countdown at the Sky Tower was followed by a firework and laser display.

Over in Europe, preparations are in full swing – including enhanced security precautions. Cities which have suffered recent terrorist attacks are not taking chances. In Berlin, barriers have been installed around the landmark Brandenburg Gate to protect revellers. Twelve people were killed in the city on 19 December when a hijacked lorry was driven into a busy Christmas market.

Meanwhile, security has been enhanced in Cologne, Germany, in an attempt to prevent a repeat of last year's widespread law breaking. A series of robberies and sexual assaults took place in the city, which were blamed largely on migrants.

In Paris, where terrorists killed 130 people in November 2015, armed soldiers are patrolling tourist attractions including the Eiffel Tower and the Arc de Triomphe. Even so, 600,000 spectators are expected to gather on and around the Champs-Elysees. French Interior Minister Bruno Le Roux said: "We must remain vigilant at all times, and we are asking citizens to also be vigilant."