Ms Rhiannon, a keen cyclist, said the 7.7kilometre cycleway was a ``gem'' which surrounding communities had fought to secure and it ``could not be lost''.

Last Wednesday Ms Rhiannon saw what cyclists are worried about when she completed the return journey from Prospect Reservoir to the Sydney Water Pipehead at Albert Street, Guildford with members of the Canal Reserve Action Group (CRAG).

The group says when former NSW planning minister Frank Sartor approved Boral's application to redevelop the last section of the old Prospect gravel quarry as the Southern Employment Lands in 2004, a bridge was included in the plans.

The bridge was to provide a safe crossing of the soon-to- be-completed Reconciliation Drive, which traverses the new industrial estate and links the Prospect Highway at Prospect with Widemere Road at Wetherill Park.

Former Holroyd councillor and CRAG member Ken Morrisey, who rode with Ms Rhiannon, said the original plans included a bridge.

``But by late 2007 or early 2008 the bridge had disappeared, replaced by a set of traffic lights,'' he said.

Members of CRAG say they have figures that show 300,000 vehicles would use the road each week, putting at risk the safety of cyclists, particularly children, crossing it at road level.

``It will seriously compromise one of the safest cycleways in Sydney,'' said CRAG member Fred Crowe.

Ms Rhiannon promised to ask about the bridge when Parliament resumes next month and said she would also raise the matter during budget estimates hearings

in September and October.

``To lose [the bridge] would be a huge loss and installing a set of traffic lights is just plain dangerous,'' Ms Rhiannon said. ``It's a major road with huge B-doubles and a set of traffic lights will put lives at risk.''