A small group of sheep are causing a headache for the NSW government, which has been accused of “discarding” the flock and "leaving it to rot".

The Curtain Call sculpture, featuring four bronze rams and a shearer’s ramp, by renowned artist Les Kossatz had been displayed in Darling Harbour for almost 20 years, but the artwork was removed by the state government around 2015 as part of the redevelopment of the area, according to Sydney Lord Mayor Clover Moore.

The NSW government said safety concerns had delayed the reinstallation of the Curtain Call sculpture by Les Kossatz.

“The lambs from the statue currently sit disassembled in a nearby light rail depot,” Cr Moore wrote in a letter to Melinda Pavey, NSW Minister for Water, Property and Housing.

Ms Pavey said the artwork had not been reinstalled because it required "considerable restoration" and had been deemed a climbing hazard for young children.