PRIME Minister Tony Abbott has been forced to defend the reputation of the Australian Border Force after yesterday’s public outcry against an impromptu crackdown on anti-social behaviour and visa cheats in Melbourne.

Operation Fortitude — involving the new border agency, Victoria Police, the Sheriff’s Office and taxi industry officials — was to begin Friday night.

But Victoria Police was forced to call if off when an ABF media release announcing it caused outrage on social media and a snap protest outside Flinders St station.

Speaking at a press conference today, Mr Abbott blamed the debacle on a “badly-worded press release”, and said that those who demeaned the role of the Australia BorderForce should be “a little ashamed of themselves”.

“They do their job on our borders, on our airports, in the seas, to our north,” Mr Abbott said.

“I think the Australian Border Force does an absolutely outstanding job, and the idea that they should be pilloried on the basis of a badly-worded press release is shameful.

“They will be present where they need to be to do their job, and I think Australian people are extremely grateful for that”.

Mr Abbott credited the force with a “75 per cent increase in air cargo screening, and a 25 per cent increase in sea cargo screening”.

“And it is because of their work that we’ve stopped the boats, stopped the deaths at sea, stopped all these illegal arrivals which were happening at the rate of almost 5000 a month at their peak under the last government.”

The police movement caused massive backlash in Melbourne’s CBD yesterday afternoon, with hundreds of people flooding the city to protest against the random targeting of citizens by the police.

Protesters called the ABF “fascist”, “the Gestapo” and referred to the crackdown as “a racist disgrace”.

“You need to be aware of the conditions of your visa; if you commit visa fraud you should know it’s only a matter of time before you’re caught out,’’ the ABF media release said.

Minutes later the Border Force — part of the Immigration Department — tried to clarify the message by saying officers would not be “stopping people at random”.

Its chief, Commissioner Roman Quaedvlieg, on Friday night vowed “internal disciplinary” measures over the communication stuff-up.

Speaking to Sky News today, Assistant Education Minister Simon Birmingham said it was up to Mr Quaedvlieg to find out what went wrong.

“It’s really now up to him to get to the bottom of how this mistake occurred within his agency,” he said.

“Clearly, this was an erroneous statement, it was a misleading statement ... and it was a mistake on their part to issue a statement of this nature.”

Meanwhile, Greens Senator Sarah Hanson-Young has called for the powers of the ABF to be clarified.

“It needs to be cleaned up; they’re not an arm of the military and they’re not a police force,” she told the ABC.

Opposition leader Bill Shorten said today that it took some time for the full magnitude of Operation Fortitude to sink in before he realised it was a bad “police state” look for Melbourne.

Mr Shorten was initially not too critical of the Border Force operation on Friday, but after it was abandoned, he strongly denounced it.

Speaking with reporters on the sidelines of the West Australian Labor conference on Saturday, he described it as “one of the most catastrophically silly ideas I’ve seen this government do”.

“To be honest, I couldn’t believe what I was hearing,” Mr Shorten said.