A MASS bird poisoning which left more than 50 Corellas dead near Tamworth three weeks ago is still under investigation by environmental agencies.
NSW Environmental Protection Authority (EPA) confirmed on Tuesday a number of the birds found dead at Manilla last month had been sent to Taronga Zoo in Sydney for testing.
A spokesman from the EPA said samples from the dead birds are currently being analysed in a laboratory.
The authority could not confirm when the test results are expected to be known.
A local wildlife carer alerted the EPA after more than 50 Corellas were discovered dead or seriously injured in Manilla, near Tamworth, on March 31.
The affected birds were found in Strafford Street, on the north-eastern side of the town, and around Viaduct Bridge.
The EPA launched an investigation, which is ongoing.
Authorities are concerned the apparent poisoning was a "deliberate" act.
EPA Manager Regional Operations North Branch Lindsay Fulloon said at the time the EPA was appealing for information on the "apparent mass poisoning of native birds".
"This appears to be a large scale targeting of the birds and we are concerned that it could have been deliberate," he said.
The EPA is urging anyone with information about the bird deaths to contact the environment line on 131 555 or email firstname.lastname@example.org. The EPA said information reported by the public will be treated confidentially.