Work on around 40% of construction sites visited in Lancashire, Cumbria and Cheshire has stopped after failing a two-day inspection by The Health and Safety Executive.
In total, 1,500 construction sites are being targeted across the UK as part of a new campaign, which includes 200 in the North West.
The Health and Safety Executive carried out inspections at 37 sites in Barrow, Kendal, Lancaster and Morecambe, and issued 15 enforcement notices.
The HSE carried out inspections at 66 sites across Cheshire and issued 28 enforcement notices.
Eight of the notices within Lancashire and Cumbria concerned unsafe work at height, including working on dangerous scaffolding or where guard rails were missing. The rest dealt with asbestos, poor electrics, and the general state of sites.
In Cheshire, 14 notices concerned the welfare of workers, equipment, electrics and the general state of sites.
Mark Cottriall, HSE principal inspector for Lancashire and Cumbria, said: "None of the issues we had to deal with were unusual, and everybody in the industry should know what steps they need to take. People may think they can save time or money by ignoring the rules but it simply isn't worth the risk."
Wayne Crumpton, HSE principal inspector for Cheshire, added: "Our prime concern is to ensure the safety of workers and the public, and we will always offer help and guidance to contractors. However, if our advice is ignored or we find poor standards we will not hesitate to stop work, or even prosecute companies."
The HSE is targeting construction sites in Rochdale, Oldham, Barrow, Kendal, Lancaster, Morecambe, Macclesfield, Knutsford, Crewe, Nantwich, Congleton, Chester, Warrington, Northwich, Ellesmere Port, Neston, Runcorn and Widnes in the North West.