Former US president Barack Obama is set to catch up with Prime Minister Malcolm Turnbull “for a chat” after touching down in Australia for a private speaking engagement.

Mr Obama arrived at Sydney Airport at lunchtime on Friday ahead of an invitation-only event at the Art Gallery of NSW hosted by the New Zealand-United States Council.

A motorcade of vans, SUVs and more than a dozen police motorbikes transported Mr Obama from the airport to a hotel in Sydney’s CBD.

Police helicopters swirled above the building as he was driven through the city to a pre-arranged meet-and-greet at the Sydney Opera House.

The ABC is reporting Mr Obama, who has more than 15 million Twitter followers, is due to speak at the gallery on Friday night. It is unclear who is on the guest list and there were no tickets available for purchase.

Barack Obama arrives in Sydney ahead of secretive speech https://t.co/ZeBFKgwFo5 pic.twitter.com/9vQ0aqtse4

— ABC Sydney (@abcsydney) March 23, 2018

#Obama at the #OperaHouse: @BarackObama getting a special tour of #Sydney icon. Follow his visit on #7News @4&6pm pic.twitter.com/cl5orwDLKe

— Paul Kadak (@PaulKadak) March 23, 2018

Mr Obama, the 44th US president, flew in from New Zealand where he met Prime Minister Jacinda Ardern and former leader John Key on Thursday.

Actor Sam Neill hosted Mr Obama in a private dinner that night.

Australian Prime Minister Malcolm Turnbull said he was due to “catch up and have a chat” with the former US president who’s on a week-long tour of New Zealand, Australia, Singapore and Japan.

“I look forward to catching up with President Obama when he’s visiting,” Mr Turnbull told reporters on Thursday.

“Of course, he’d be a very welcome visitor, albeit briefly, to Australia.

“We’re just going to catch up and have a chat.”

The New Zealand-United States Council chairman Leon Grice said “President Obama’s presidency had an extraordinary impact on the world”.

“During his service, New Zealand’s deep friendship with the United States was strengthened politically, culturally, in trade and investment, innovation and security,” Mr Grice said.

New Zealand Prime Minister Jacinda Ardern catches up with Mr Obama during a traditional Maori welcome at Government House. Photo: AAP

After arriving in New Zealand on Tuesday night, Mr Obama was whisked away for a game of golf with Mr Key.

The two former politicians, who have teed off together several times before, headed to Kauri Cliffs, a par 72 championship golf course ranked 39th in the world by Golf Digest.

Mr Key said hosting the former US president would lead to tourism benefits.

“He’s still one of the most influential people on the planet,” Mr Key told NZ radio.

“From a New Zealand-US perspective [this is] really important, and from a tourism perspective the reality is there’s 100 million people [who] follow him.”

Mr Obama is on a week-long tour of Australia, New Zealand, Singapore and Japan, with Tokyo the next stop after Sydney.