More than three-quarters of maritime professionals believe a strategic waterway or major port will be shut down within two years because of a cyber-attack, according to a new study.

Research by classification society DNV suggests the growing threat of attack is likely to result in problems such as grounded ships and collisions.

Nine in 10 of those asked believed that ship or fleet operations would likely be disrupted in the coming years — more than half expected cyber-attacks to cause physical injuries or deaths.