Auckland's Mayor says the Central Rail Link project hasn't derailed,  despite concerns from the Auditor-General.

A report from the Auditor-General's office praises the project's governance, but has found its budget and timeline is likely to change.

It's found supply chain disruption, rising material costs, and trouble recruiting overseas expertise is all contributing.

Phil Goff told Mike Hosking he knows despite challenges, that the project will stay on track.

He says he's been through the tunnels and seen the boring machine at work.

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