The commemorative installations were to have been unveiled at the Meeting of Two Cultures ceremony on Wednesday, but it was cancelled due to the coronavirus outbreak.

Instead, the sculptures were erected quietly and visitors to the historic precinct on the weekend were both surprised and captivated by the new public art.

After a tender process and subsequent short list presentations by various artists and sculptures, the Kamay 2020 Project Board selected works, which are described as "sensitive, balanced and include story-telling of both Aboriginal and European viewpoints of the arrival of the Endeavour".

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Julie Squires and Theresa Ardler, of ThinkOTS, were commissioned to install two sculptures, the Whales and the Nawi (Canoes), while artist Alison Page and Nik Lachacjzak, of UAP Australia, created Eyes of the Land and the Sea.

Prime Minister Scott Morrison said, "The day Cook and the local Indigenous community at Kamay first made contact 250 years ago changed the course of our land forever".

"On this very special 250th anniversary of this moment in our history, these stunning new installations at Kurnell capture the view from the ship and the view from the shore in a magnificent way," he said.

"They will stand for generations to come and enable us to reflect upon our unique and shared history.

"The anniversary is a merging of our histories - a point in time from which we embarked on a shared journey, which is realised in the way we live today.

"Our shared history tells the story of all of us.

"We honour the resilience, wisdom, custodianship and stewardship of Aboriginal and Torres Strait Islander Australians. Indigenous culture is a fundamental element of modern Australia.

"We also acknowledge the extraordinary individual of James Cook whose passion for science and discovery played such a critical role in Australia's journey to the nation we are today."

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Mr Morrison said, while there was already a monument for Cook at the landing site, it was designed in line with the symbolism of its time.

The new installations were thought to be appropriate to mark the 250th anniversary, symbolising not only Cook's landing but also his meeting of the local Indigenous people.

In preparation for the 250th anniversary, Sutherland Shire Council and the federal and state governments consulted with the La Perouse Local Aboriginal Land Council.

The council's chairwoman Noeleen Trimbery said, "I am proud to have participated in the selection of the commemorative installations, and feel that they help to represent the ongoing connection of the Gweagal people to the area".

"The sculptures are an important element in commemorating the Endeavour arrival, but they are also tremendously important in showcasing that Aboriginal people continue to have spiritual and traditional links to this place.

"Many families and Elders from the La Perouse Aboriginal community have special ties to Kurnell, and my hope is that these new sculptures bring some balance in the story telling of our shared history."

Cronulla MP and Attorney-General Mark Speakman said, "I've long lamented the neglect of Kurnell and Kamay Botany Bay National Park, notwithstanding their seminal role in our nation's history".

"There are many interpretations of that history, but we can't walk away from it - a nation with a vision for its future has to understand its past," he said.

"These installations, the first stage of $50 million of park upgrades, will help us to talk about and understand that history.

"They commemorate the past - the meeting 250 years ago of the oldest living culture in the world with the enlightenment values and scientific inquiry of James Cook and his crew - and they symbolise our shared future."

The $50 million upgrade of the historic precinct, jointly funded by the federal and state governments, was announced in 2018.

Other stage one projects include restoration and repairs to Alpha House, conservation works to the 1870 Cook Obelisk and repairs to toilets at Commemoration Flat and Cricketers Pitch.

Planning and design for other elements of stage one, including a new visitors centre are underway.

Future works are to include the construction of new wharves at Kurnell and La Perouse, allowing the restoration of a ferry service if an operator can be found.

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