There have been numerous attempts to cheat in this year's Bird of the Year competition, Forest & Bird has revealed.

More than 300 votes from a single IP address were logged on Wednesday night. Forest & Bird said the "dubious" votes were picked up scrutineers Dragonfly Data Science.

"We had 310 dubious votes for the shag from an IP address in Australia," the Bird of the Year hosts said on Twitter. "Thankfully, @dflydsci are on the case as our official scrutineers. They picked up the votes and shut them down."

A graph shows the shag, also known as kawau, was struggling near the bottom of the pack before the suspect votes began rolling in just before 6pm. By 10pm, the shag had overtaken the little penguin, albatross, bellbird, royal spoonbill and many others.