Roadworks have been installed on the A78 in West Kilbride which could last for up to 21 working days.
Scotia Gas Networks (SGN) set up the roadworks unannounced on Monday with some queues emerging during rush hour.
The area affected is Ardrossan Road, near the Seamill Hydro hotel.
The SGN website explains: "We look after more than 74,000 kilometres of pipes across our network.
"Making sure these pipes deliver your gas safely and reliably means that we need to upgrade or repair them at times.
"We know that roadworks can be frustrating, but our essential work keeps you, your family and local community safe.
"When upgrading pipes or installing a new connection, we can plan the roadworks in advance.
"But when safety is at stake we must respond quickly and efficiently, and this may mean having to carry out streetworks at very short notice or at night."
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