The West Australian Quarantine Inspection Service has lifted its quarantine at an Esperance property relating to the interstate discovery of Wheat Streak Mosaic Virus (WSMV).

Department executive director of plant industries Rob Delane said the decision to lift the quarantine coincides with a review of restrictions introduced last week on interstate seed movement.

"The latest information is that the virus is widespread in some states and may have been present in low background levels for sometime," Mr Delane said.

"There has been speculation that the virus could be spread by seed. It stands to reason that if it was seed borne, we would have the virus in West Australia, but we haven't detected it so far," he said.

"We've completed more than 13 000 samples and all tests have been negative."

The Western Australian Department of Agriculture will continue targetted surveillance for signs of the virus and its known vector the Wheat Curl Mite, but currently cannot justify maintaining the restrictions on seed or the sowing of seed imported from interstate.

The Department will be providing management advice to the owner of the Esperance breeding site for him to discuss with his clients. Mr Delane commended the site owner for his cooperation throughout the process.

Mr Delane said if there is a positive test result for the virus in the future, the Department would employ standard operating procedures for exotic incursions, and work quickly to determine the pathway of infection and spread, before making a decision about whether eradication is feasible or not.

"We need to maintain a flexible and responsive approach, which allows us to delay the entry of WSMV into West Australia for as long as possible," he said.

"The Department will continue to sample the south coast of the State that is the most favourable area for the virus or its vector which would need green material year round to flourish. Glass houses and irrigated plots will also be monitored.

"Surveillance for the mite will also continue in spring in those highly favourable areas."

In addition, Wheat Streak Mosaic Virus is to be listed as a notifiable disease, which would require researchers and growers to report any signs of the virus.

All known seed importers are being advised of the changes to the restrictions and that the virus is now a notifiable disease.

Mr Delane said the restriction on importing living host plant material such as some grasses within nursery stock remains in place.