Central west Local Land Services senior biosecurity officer Rhett Robinson said there had been 130 reports of locust activity since January.

"We've had reports in areas such as Gilgandra, Collie, Armatree and Curban," he said.

"Locusts have been reported north in Gulargambone and east in places such as Mendooran."

Mr Robinson said one of the biggest risk factors was medium density swarms wiping out newly emerging crops.

"They nip off the growing tips," Mr Robinson said.

"Medium density swarms are usually 10 adults per square metre, and high density swarms are 50 plus."

Mr Robinson said locusts preferred cereal crops, including oats and wheat.

"There have been reports of crop loss to lucerne, where they strip all the leaves off, doing a lot of damage," he said.

He said effective locust response relied on community support and reporting.

"Report any medium density swarms," he said.

"Spray when hatched and for flying swarms it is best to spray early in the morning."

Mr Robinson said a biosecurity officer would respond with a phone call or a site visit within 48 hours of a locust report being received.

This was the standard set by the Department of Primary Industries (DPI) - the lead agency with plague locust control. Local Land Services is the co-ordination support agency.

Chemical volume and type would be issued according to the infestation size and the species, he said.

Chemical would not be issued over the counter (as per DPI Policy and Procedure) without a prior inspection or prior arrangement from staff.

"In the early stages of the campaign, chemical will not be issued without an inspection," said Mr Robinson.

"This is a requirement of legislation and to determine species and size of the problem across the local area."

Landholders need to have a current AQF3 chemical user card to apply chemical.

Landholders are required to sign for all chemical issued and expected to comply with the label recommendations.

Nobody has yet been refused chemical in the 2014-15 campaign.