A memorial service has taken place in Sydney to remember the Royal Australian Navy's deadly first single ship battle.

The Bradleys Head service was part of the International Fleet Review, marking 100 years since the Navy's first warships entered Sydney Harbour.

In 1914 during World War I, HMAS Sydney encountered German cruiser Emden off the Cocos Islands.

Four Australian sailors lost their lives in the battle, which also killed 134 Germans.

At the service, the mutual respect and compassion between the two side was recognised with an exchange of gifts: a cross from the Emden and a red kangaroo from the Sydney.

The service also recognised all who have lost their lives while serving on the Sydney, including the 645 sailors killed off Western Australia in World War II.

Navy Chief Vice Admiral Ray Griggs said the conduct of those involved in the battle is a credit to both nations.

"Once the battle was over, there was respect, care and concern for the injured," he said.

"The 50 wounded German sailors were cared for by Sydney's medical team and taken to the nearest hospital in Colombo for treatment.

"These were the hallmarks of the way that Emden had conducted herself over the preceding months."

Tall ships on display in Sydney

Continuing the fleet review celebrations, more than a dozen tall ships were on display today on Sydney Harbour.

The public were also able to board international warships at Barangaroo and Garden Island, to get a glimpse of life at sea.

On Saturday, Prince Harry and Governor-General Quentin Bryce performed the official review of warships from 17 nations.

Up to a million people are estimated to have watched a huge light and fireworks show which lit up Sydney harbour to end the day's celebrations- the biggest since the Olympic Games.

The dazzling fireworks display was launched from city rooftops, barges, the Harbour Bridge, and the decks of Navy warships.

Images of key moments in the Navy's history were projected onto the Opera House along with archival sound recordings, honouring Australian sailors who have lost their lives at sea.

Prince Harry leaves Sydney following review

Prince Harry is spending the day in WA after inspecting vessels with the Governor-General in Sydney. ( AAP/Getty Images: Ryan Pierse )

Earlier today the International Fleet Review's star guest, Prince Harry, flew out of Sydney.

At the airport, he said he thought of the city as a second home.

"Very sad to be leaving Sydney, it's been absolutely fantastic, the weather's been beautiful which is very lucky for us, just, as I said, really sad to be leaving," he said.

"Work - just can't get the time off work these days."

The young royal is briefly stopping over in Perth before wrapping up his fleeting first official visit to Australia.

In Perth he met WA Premier Colin Barnett and his wife, before meeting SAS troops in Perth and visiting the Campbell Barracks at Swanbourne.