More bonded asbestos fragments have been discovered inside recycled mulch used on government projects.
Transport for NSW said on Tuesday landscaped areas near two stations being converted from heavy rail to metro standards had been identified as having mulch containing the bonded asbestos.
Belmore Station and Punchbowl Station sit in Sydney's southwest along the T3 line, where buses are due to replace trains as the track is converted for several months.
Sydney Metro is working with contractors to review sites where landscaping work has recently been completed.
The asbestos was found in areas that have been fenced off and the agency says the bonded asbestos, first discovered in recycled mulch at the Rozelle Parklands in Sydney's inner west in January, was lower risk than friable asbestos that can crumble into dust and become airborne.
Two garden beds on a project on the state's south coast have also been fenced off after samples showed bonded asbestos fragments.
The agency said it is working with contractor Fulton Hogan to prepare a remediation plan at the site of the project to build a new four-lane bridge over the Shoalhaven River at Nowra.
All impacted mulch at the site will be replaced, Transport for NSW said in a statement.
