Chinese Warships Dock In Sydney Harbour

Three Chinese warships have sailed into Sydney Harbour.

The People's Liberation Army frigate, an auxiliary replenishment ship and an  amphibious vessel arrived on Monday morning and docked at Garden Island.

The ships, which are carrying 700 personnel, are expected to stay in Sydney for four days.

Chinese warship sydney harbour
Photo: 10 News First

While the arrival of the warships in Sydney was not publicly announced, Prime Minister Scott Morrison said their docking had been planned for "some time".

"It was a reciprocal visit because Australian naval vessels had visited China," Morrison told reporters in the Solomon Islands.

Morrison said the vessels were returning from a "drug trafficking operation" in the Middle East.

"It may have been a surprise to others, but it certainly wasn't a surprise to the Government," Morrison said.

Photo: 10 News First

READ MORE: What The South China Sea Showdown Means For Australia

However, the timing of the arrivals has raised eyebrows.

Morrison is currently visiting the Solomon Islands, at the same time regional leaders meet at the Shangri-La Dialogue in Singapore.

China's growing role in the Pacific through funding infrastructure and boosting defence links was a hot topic in Singapore, with Beijing choosing to send its highest-profile defence delegation ever to participate in the forum, led by Defence Minister Wei Fenghe.

Photo: 10 News First

This week also marks the 30th anniversary of the Tiananmen Square massacre that killed hundreds.

READ MORE: Extradition Battle Looms On Eve Of Tiananmen Massacre Anniversary

READ MORE: Tiananmen Square: 30 Years On, And The Government Still Won't Talk About It

Fenghe told the Shangri-La Dialogue the bloody crackdown on protesters around Beijing's Tiananmen Square 30 years ago was the "correct" decision, citing the country's "stability" since then.

Photo: 10 News First

Morrison was quick to dismiss the connection between the timing of arrivals and the anniversary of Tiananmen Square.

"Any reading into timings could be subject to a bit of over-analysis," he said.

Disputes over islands in the South China Sea have seen tensions rise, particularly between the U.S. and China.

It was revealed last month an Australian ship was followed by a Chinese vessel as they sailed through the South China Sea.

Australian military pilots flying over the disputed area also had lasers pointed at their planes in recent times.

The Department of Defence has been contact for comment.

With AAP.