Drivers experienced gridlock on the M1 Princes Motorway between Shellharbour and Wollongong on Sunday, as a result of both the popular Wings Over Illawarra show at Shellharbour Airport and the closure of Windang Road following an alleged shooting incident.

Some people reported getting stuck in traffic for an hour.

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Kiama MP Gareth Ward - for whom the $630 million bypass was a pet project - said he was not concerned about the road's traffic capacity after the weekend's jams.

"I'm confident these two events resulted in a unique situation we won't expect to see again in the foreseeable future," Mr Ward said.

He noted the size of Wings Over Illawarra, which billed itself as Australia's largest annual airshow and attracted thousands of spectators to the area.

Mr Ward said the traffic congestion was simply the result of an "unlucky" circumstance.

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"Can you imagine how much worse it would have been if we didn't have the Albion Park Rail bypass?" he said.

A Transport for NSW spokesperson said the bypass was built to cater for typical morning and afternoon peaks in traffic, based on traffic growth over 20 years.

"It is anticipated the bypass will cater for these predictions and will significantly improve holiday traffic travelling to the South Coast in the vicinity of the project," the spokesperson said.

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