The design of the 2.6 metre high prefabricated barricade, which started to go up this week, has already been almost universally condemned as intrusively ugly and a betrayal of the democratic principles embodied in the Italian-born architect's competition winning plan.

Leading architects, Glenn Murcutt and Ken Maher, have described the fence as "terrible", saying it will compromise the "moral rights" held in the building.

"Giurgola designed this building so that you had very good access to the people - so it expressed freedom," Mr Murcutt said. "Putting a fence around it is putting a noose around it".

While these remarks will almost certainly strike a chord with the tens of thousands of Australians, many of whom are Canberra residents, with fond memories of rolling down the grassy slopes of the building's roof, the fact remains it is a terrorist target.

The need for tighter security has been being canvassed for many years and took on new urgency after the 2014 terrorist attack on the Canadian Parliament and adjacent war memorial in Ottawa that left two people, including the ISIL-inspired attacker, dead.

2014 was also the year Australian security agencies intercepted terrorist chatter about a possible attack on our own, 250,000 square metre, parliament building.

Such threats just can't be ignored given that in addition to housing hundreds of MPs and Senators and thousands of staffers, support personnel and journalists, the $1.1 billion, 4,700 room edifice attracts more than 1 million visits a year. There can be up to 2,700 people inside at any one time.

The product of a gentler age when Australia was not high on the hit lists of international terrorists, the building was originally designed without "in your face" security barriers, bollards, fences and the like.

That has now changed forever with this week marking a sharp transition in the building's outward appearance and the way it presents itself to the world.

While there is an argument that this, in some ways, is a tacit admission that the terrorists have won by forcing us to change the way we live and behave, the issues are more complex than that.

Nobody is talking about changing the way we elect our political representatives or conduct the business of the Lower House or the Senate.

The new structure, along with less visible and high tech security upgrades that are being installed at the same time, should be seen in the same light as the bollards that are now becoming a feature of many public spaces in Australian cities as well as overseas.

Taking sensible precautions to deny terrorists easy access to high value targets is not the same as giving in to them.