In Old Portsmouth, on the walkway by the sea wall near the Square Tower.

Australian Settlers
Plaque 1

Plaque 2

Plaque 3

Plaque 4
Click images above to enlarge
Australian Memorial
Inscription - Plaque 1
Britain and Australia
"Bonds of Friendship"
Unveiled by
11th July 1980

Inscription - Plaque 2
This Monument Commemorates the Sailing
from Spithead on 13 May 1787
of the First Fleet Conveying Settlers to Australia
A Great Nation was Born

Inscription - Plaque 3
This Block of Granite was Quarried in New South Wales
and given by the Citizens of Sydney, Australia
The Plinth of the Monument was Unveiled on 13 May 1976
By The Honourable SIR DAVIS HUGHES
Agent General for New South Wales

Inscription - Plaque 4
This memorial and it's twin in Sydney Cove, Australia
was the concept of Austin C. Spraggs Esq.
'A Man of Portsmouth'
Sculptor : John Robinson

Further Information
The sculpture recalls the sailing of the First Fleet of settlers from Spithead to Botany Bay, Australia, on 13 May 1787. The Fleet was led by Captain Arthur Phillip RN. Today it is a reminder of Portsmouth's past links with Australia and is a token of friendship between the two countries.
The memorial is called 'BONDS OF FRIENDSHIP' and was unveiled by The Queen on the 11th July 1980.
A twin monument was unveiled at Circular Quay, Sydney, Australia in 1980 as part of the Bicentenery Celebrations. The photo (borrowed from John Robinson's site, Bonds of Friendship) shows the unveiling. The memorial was later moved to Loftus Street.
See Also
The model of the original ship H.M.S. Sirius at Gunwharf, the First Fleet Re-enactment Plaque and the Birth of Australia Memorial.