Last week the bronze memorial, commissioned in 1936 after the death of Queen Elizabeth's grandfather, was damaged as vandals splattered red paint around its base in an apparent reference to blood.

A paint-soaked sheet was attached to the main statue, and bronze plaques commemorating Australian servicemen and wartime doctors and nurses were spray painted red.

Plaques recognising Sir Henry Parkes, Sir Samuel Griffith, Sir Edmund Barton and Sir George Reid were also damaged as well as the granite base and iconography related to the British monarchy.

As Duke of York, George V opened the first Federal Parliament in Melbourne in 1901 and his son, later George VI, opened Old Parliament House in 1927.

A National Capital Authority spokeswoman said the damage would be removed as soon as possible. It was identified on Monday after part of a daily inspection of more than 100 memorials and ceremonial sites around Canberra that make up the National Estate.

The memorial's bronze statue and medallions had cleaning and conservation works completed in March 2014, ahead of the visit to Canberra by the Duke and Duchess of Cambridge and their son Prince George, named for his great-great-great-grandfather.

"The NCA arranged a conservator and stone-cleaning specialist to assess the graffiti and advise on the best cleaning approach," the spokeswoman said.

"Techniques used by specialist sub-contractors to remove the graffiti vary based on the surface, in this case sandstone and bronze."

A stonework conservation program will begin on the memorial in the next few months, and is set to include stone repointing, conservation and cleaning.

Designed by sculptor George Rayner Hoff and architect Harry Foskett, the bulk of the structure was built in 1941 but the plaques and bronze statue were delayed by World War II.

Both men died before its completion and John E. Moorfield was chosen to finish the memorial.

Officially unveiled in March 1953, more than 17 years after it was first commissioned, the statue of King George faced Parliament House, while a stone depiction of Saint George faced the Australian War Memorial in recognition of George V's wartime leadership of Britain and the Commonwealth.

The memorial originally stood directly opposite Old Parliament House, about 50 metres from King George Terrace and blocking the view from Parliament to the War Memorial.

Originally planned before the creation of Lake Burley Griffin, the memorial was considered by many, including Interior Minister Doug Anthony and founding National Capital Development commissioner John Overall, to be an impediment to the view to Mount Ainslie.

Prime Minister Sir Robert Menzies gave approval for the memorial to be moved to its current location before his retirement in 1966.

Since 1968, the memorial has stood on King George Terrace, near the site of the Aboriginal Tent Embassy and the Senate rose gardens.

Graffiti or other damage found on any of Canberra's national assets or land is removed as soon as practicable, the spokeswoman said.