SYDNEY - The virus responsible for Covid-19 can survive for up to four weeks on surfaces including banknotes and mobile phone screens, researchers have claimed.

Australia's national science agency CSIRO found the virus was "extremely robust" at 20C (68F), or room temperature, and survived for less time at hotter temperatures.

The research involved drying virus in an artificial mucus on different surfaces, at concentrations similar to those reported in samples from infected patients and then re-isolating the virus over a month.

The study was also carried out in the dark, as research has demonstrated direct sunlight can rapidly inactivate the virus.

Dr Debbie Eagles, deputy director of the Australian Centre for Disease Preparedness, said: "Our results show that SARS-CoV-2 can remain infectious on surfaces for long periods of time, reinforcing the need for good practices such as regular handwashing and cleaning surfaces.

"At 20 degrees Celsius, which is about room temperature, we found that the virus was extremely robust, surviving for 28 days on smooth surfaces such as glass found on mobile phone screens and plastic banknotes.

"For context, similar experiments for Influenza A have found that it survived on surfaces for 17 days, which highlights just how resilient SARS-CoV-2 is."

The findings, published in Virology Journal, suggest the virus survives longer on smooth surfaces such as glass, stainless steel and vinyl, compared to porous surfaces such as cotton.