US scientists have created a synthetic SARS-like virus, sparking fears about the increasing ease with which bioweapons could be created in test tubes.
The bat virus, engineered to infect mice, is the largest replicating synthetic organism ever made.
The director of Australia's National Centre for Biosecurity, Professor Ian Ramshaw, said the move signalled a new wave of problems in biosecurity.
''They were allowed to create a new virus without absolutely knowing how dangerous it might be,'' Professor Ramshaw said.
''It's getting very, very easy now to make these things in the test tube.''
SARS, severe acute respiratory syndrome, emerged almost six years ago, making more than 8000 people sick and killing nearly 800.
Symptoms are similar to influenza, including inflammation of the lungs, a cough, high fever and gastrointestinal problems.
Scientists believe the virus may have originated in bats.
United States researchers from the Vanderbilt Medical Centre and the University of North Carolina at Chapel Hill generated the synthetic bat virus to try to understand how it might have jumped from bats to humans. They have reported their findings and descriptions of the virus in the Proceedings of the National Academy of Sciences.
Professor Ramshaw said people did not need lot of expertise to produce a virus once they knew its genetic sequence.
All that was required was to send the sequence to a ''designer DNA firm'', which would create the sequence. ''There's no regulation of these designer DNA firms around the world that prevents them from making these sequences that I will send off in an email and it will be sent back in the post,'' he said.
''You don't have to have a sophisticated laboratory to do this.''
The US researchers said they acknowledged potential safety concerns and encouraged ongoing external safety reviews at all stages of design and creation of the virus.
They conducted studies on all bat viruses, even weakened mutants, under the same biosafety conditions used to study SARS. They found human antibodies that knew how to render SARS non-infectious also neutralised the bat SARS-like virus, providing another safety measure.
Research co-leader Professor Mark Denison said their work addressed fundamental questions about virus movement between species.
''It also could improve public health preparedness by allowing rapid responses to naturally emerging or intentionally introduced zoonotic pathogens,'' Professor Denison said.
Professor Ramshaw called for regulations to limit availability to these kinds of technologies.
DNA firms could subscribe to regulations to screen for dangerous products, but they were voluntary.
''The problem that we've got is we have no regulations in Australia about it,'' Professor Ramshaw said.
''This is a new life, a bat virus. Just by the sequence they've found, they've made the virus come alive with the new technology, and we haven't got any regulations in place to control and ensure there's no security risks associated.''