The Wellington City Council is keeping a close eye on earthquake demolition sites across the city as a significant weather low moves in.

Severe northwest gales of up to 160 kilometres per hour are forecast from this afternoon.

Meteorologist Lisa Murray said this was a very strong wind event for Wellington.

She advised people to tie down trampolines, and said it is really going to show up the weakness for anybody with a loose roof.

"Also for the likes of Wellington where we have some buildings that are being knocked down the debris could be caught up in winds of this strength" she said.

A council spokesman said all the demolition sites are already safely secure and work will stop if it gets too windy.

He said demolition has stopped a number of times before due to the weather.

Meanwhile, the Transport Agency is advising those with motorcycles and high sided vehicles to stay off the roads.

Regional Performance Manager Mark Owen said winds of this strength can really blow vehicles around, especially on State Highway Two over the Rimutaka Hill.

"Particularly through the cuttings where you get accentuated wind, there's a risk they could get blown off the road or at worse into the path of an oncoming vehicle."