Covid 19 coronavirus: Fleeing Auckland - massive number of cars left Auckland on Saturday night

Southbound traffic on SH1 near Mercer peaked at 11pm on Saturday night just hours before the city's fourth lockdown. Graphic / NZTA

There was a massive surge in the number of vehicles heading south and away from Auckland on Saturday night - within hours of Prime Minister Jacinda Ardern announcing the city would be locked down for a fourth time.

The latest figures from the New Zealand Transport Agency show the roads leading out of the city were up to 600 per cent busier than usual and comes after leading microbiologist Dr Siouxsie Wiles yesterday blasted Aucklanders thinking of fleeing their city for the bach, saying it was "a s****y thing to do".

Wiles wrote on Twitter that if they did have a genuine reason for leaving the city they needed to take alert level 3 precautions with them and act as if they could already be infectious.

Coromandel locals have commented on social media that they noticed a huge influx in visitors in the area between Saturday night and Sunday morning.

The announcement also came at a time when some people would have been visiting other cities at the weekend particularly for large events such as the Parker vs Fa fight in Auckland, Ports of Auckland Round the Bays and Six60 in Hamilton.

Auckland mayor Phil Goff also issued a similar warning to Aucklanders when the city moved to alert level 2 weeks ago telling those who were planning to head to the bach they would be turned around by police.

NZTA figures released to the Herald showed the overall increase in vehicles on the road since the announcement at 9pm on Saturday and the borders were closed at 6am on Sunday was 5000 on State Highway 1 in the southbound lane just before Mercer and 2500 east bound on State Highway 2 just after the State Highway 1 interchange.

The biggest increase in traffic came at 11pm just two hours after Prime Minister Jacinda Ardern surprised the country by announcing Auckland would move to alert level 3 at midnight on Saturday and the rest of country would move to alert level 2.

Southbound on SH1 near Mercer there were 400 per cent (or 1200) more vehicles than usual and here were also 600 per cent (500) more vehicles travelling east bound on SH2 just after the SH2 interchange headed towards Maramarua which is also the main route to some holiday hot spots such as the Coromandel.

There was also a significant increase in cars on southbound on SH1 about 5.30am has people slid through the borders just before police checkpoints were set up at 6am.

Between 40 and 50 per cent more vehicles travelling over the harbour bridge in both directions at the peak at 1am on Sunday and the traffic flow remained steady until 6am. However by 10am there was almost 60 per cent less traffic crossing than a typical Sunday.

The figures showing the number of vehicles travelling north of Auckland near the checkpoints were unavailable at the time of publishing.