LLANWERN High School sent pupils home before the last bell due to a "plumbing issue".
The secondary school, on Hartridge Farm Road, tweeted on social media that the school closed for the day because of the problem.
Parent Jane Jenkins: "I picked up my daughter 20 minutes ago.
"There's a lot of traffic by the school because we're all trying to pick up our children."
School is closed period 5 due to a pluming issue. Please check the school website for further information.https://t.co/D9RgrYtY3r
— Llanwern High School (@Llanwern_High) September 20, 2017
A spokeswoman from Newport City Council said: "I can confirm that Llanwern High has closed early due to plumbing issues.
"Norse are currently investigating/carrying out work and will aim to limit disruption as much as possible.
"Should there be an impact tomorrow, parents/carers will be notified at the earliest opportunity."
The school will re-open tomorrow.
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