Why do they need such a big flag?
Australian Parliament House flag mast and flag

DPS Auspic
Description
The flag mast above Australian Parliament House has 4, angled, stainless-steel legs, forming a pyramid-like shape. The legs are anchored into the roof above the centre of Parliament House. The flag mast rises 81 metres high and flies the Australia flag above Parliament House 24 hours a day. This photo shows a second Australian flag in the foreground.
Permission should be sought from DPS AUSPIC for third-party or commercial uses of this image. To contact DPS AUSPIC email: auspic@aph.gov.au or phone: 02 6277 3342.
Thanks for your question Sam! The Australian flag and flagmast above Australian Parliament House was designed to be a prominent and recognisable symbol of the Australian Parliament. The flag—which measures 12.8 metres by 6.4 metres—marks the exact centre of the building and was intended to be seen from most parts of Canberra. It is flown over Parliament House 24 hours a day, 7 days a week and is floodlit at night.
Parliament House is one of the largest buildings in the southern hemisphere. It is 300 metres long and 300 metres wide and has a floor area of more than 250 000 square metres. A big flag was needed to fly over such a big building!