Coalition leader Tony Abbott’s comment that those “walking down the street at 2am in Kings Cross in Sydney” who are assaulted “maybe shouldn’t be there” has been branded offensive and irresponsible by the father of an 18-year-old who was killed in a “king hit” assault in that location last year.

Thomas Kelly was killed in an unprovoked attack in July 2012 as he walked through Kings Cross with his girlfriend after 10pm.

Ralph Kelly, Thomas’s father, told Guardian Australia that Abbott’s comments were “throwaway” and “offensive”.

“Someone being king hit, by the very nature of the term, it is a coward’s hit, to hit someone who never sees it coming,” he said.

“To walk through Kings Cross at 2 o’clock in the morning is all of our right. We’re allowed to be there; it’s our democratic right to be there.”

Abbott was responding to questions from reporters as he unveiled a pledge to offer retrospective compensation to Australian victims of terrorism abroad, similar to that of compensation to domestic crime victims.

The opposition leader’s full comments were: “If you are walking down the street at 2am in Kings Cross in Sydney and you get king hit, maybe you shouldn't be there. Maybe it was an unwise place to be, an unwise thing to do. But if you do get king hit and you are badly damaged, you are helped by the New South Wales victims of crime legislation and I think that the Australian victims of overseas terrorism should get similar help.”

He had been asked whether it was right to pay compensation to victims of the 2005 Bali bombings since "there were travel warnings ... at the time not to travel there".

Ralph Kelly, a board member of the Thomas Kelly foundation which was set up in memory of the teenager and campaigns to improve improve street safety, added: “It was a throwaway comment that was incorrect. If he is saying that we shouldn’t be be in Kings Cross at 2 o’clock in the morning, he’s also saying that there is a problem. If he becomes prime minister, then he needs to do something about it.

“Consecutive state governments have given away so much in terms of liquor licensing that it [King’s Cross] has now become quite a dangerous place to be at 2 o’clock in the morning. If our politicians acknowledge it’s quite a dangerous place to be, then they need to strategize and come up with good plans to make it safe.”

He added: "It was offensive that he has highlighted the issues but doesn't go on to say what the government would do if they came into power.

"Is it an irresponsible comment? I think it is an irresponsible comment, because he's saying that something is wrong, and it's not just Kings Cross, it's right across the CBD."

A king hit is a single, devastating blow that comes without warning.

The Coalition has been contacted for comment.