The company has legally built almost three dozen of the weapons to meet a demand created by Australia's strict importation laws, and is selling them to licensed buyers for almost $9000.

It is the only company in Australia turning out the AR-15 semi-automatic rifles, which are a civilian version of the US military's M-16.

Adam Lanza used an AR-15 to murder his mother, then 20 children and six staff members at Sandy Hook Elementary School, Connecticut, in December, before shooting himself.

William Spengler jnr killed two volunteer firefighters and wounded two more on Christmas Eve in Webster, New York, also using an AR-15, after they responded to an emergency call.

In July, an AR-15 was one of the guns used by James Holmes to kill 12 people and injure 58 others during a screening of the latest Batman film at a cinema in Aurora, Colorado. This week, a 15-year-old boy is believed to have used an AR-15 to kill his parents, brother and sister in New Mexico. It has been reported that he planned to go to a local shop and kill more people after murdering his family.

The AR-15 is reportedly the most popular weapon of its type in the United States, but its role in recent mass-shootings has drawn scrutiny from gun-control advocates, who see it it as the epitome of the type of weapon they hope will be banned, as it was for 10 years from 1994.

The owner of the business manufacturing the weapons in Melbourne asked Fairfax Media not to name the company for ''security reasons'', but stressed the weapons were being made and sold legally.

''The licences aren't just issued to anyone here. There's no comparison with the United States,'' the owner said. ''It's inflammatory to link [the recent massacres] with this, to say they shouldn't be made here at all. They are made for a purpose and they are not sold to the public.

''We are the quiet minority, we just go about our business and it's very frustrating to be constantly up against it.''

Under laws in most states, the main people who can buy semi-automatic weapons are professional hunters engaged in large-scale pest control (such as culling feral animals from a helicopter), and law enforcement agencies or the military.

Victorian laws state the chief commissioner of police can also grant a ''Category D'' firearms licence if the licence is required for ''an official, commercial or prescribed purpose''. There are 23 Category D licence holders in Victoria.

The Federal Attorney General can also permit the use of semi-automatics for the production of films, as fully functioning weapons are required to fire blanks. A licensed armourer can hire the weapons to a filmmaker and must supervise their use. But weapons imported for film production must be destroyed at the end of filming or re-exported.

The company that makes the AR-15s in Australia originally began producing them to get round these restrictions, as weapons made in Australia do not have to be destroyed or re-

He said it would be difficult for the Australian film and TV industries to compete with their US counterparts if they had to pay to import the weapons and then destroy or re-export them.

The company's owner told Fairfax Media that he had decided to branch out beyond the prop market and offer them for sale to other licence holders, such as government-employed hunters.

Under gun laws introduced by the Howard government after the Port Arthur massacre in 1996, the sale and possession of semi-automatic rifles were severely restricted.

Federal Home Affairs Minister Jason Clare would not comment on the desirability of an Australian company making semi-automatic rifles.

A spokeswoman for the minister noted Australia had ''some of the strictest gun laws in the world''.

''Laws regulating the local manufacture of firearms and firearm parts are the responsibility of the states and territories,''she said.