LAKE Macquarie MP Greg Piper has called on the state government to deliver an overdue report on damage to the Sugarloaf State Conservation Area.

In August extensive mine subsidence damage was caused to the area by West Wallsend Colliery, and a waterway was accidentally grouted during remediation works. A chasm 120 metres long and 17 metres wide opened up in the reserve above the Glencore Xstrata longwall mine. Then 75 cubic metres of grout was spilled into a stream.

Mr Piper said he understood an investigation had been completed but not made public, despite a promise by Premier Barry O'Farrell to release the information.

Mr Piper wrote to Environment Minister Robyn Parker about six weeks ago, renewing his call for a report.