Pleasure craft using Southland waterways will soon have to display a name or other identification on both sides of the hull.
Environment Southland will introduce a bylaw on July 1 to make boats more easily identifiable in an emergency or for enforcement purposes.
Most pleasure craft using waterways, including harbours, rivers, Milford Sound and Lake Te Anau, must comply with the Southland regional navigation safety bylaws and display a name or other identification on both sides of the hull.
The exception will be non-mechanically powered vessels such as trailer-sailers and dinghies, as long as they are less than 6m long.
Southland harbourmaster Kevin O'Sullivan said the new provisions were included in amendments to the navigation safety bylaws last year but compliance was deferred until July 1.
Owners could choose the form of identification, as long as it was on both sides of the hull in letters at least 50mm high.
Boats that already had a name or a boat club number did not need to be renamed.
"The purpose of doing this is to make sure that recreational boats can be identified in the case of an emergency, or for enforcement purposes," Mr O'Sullivan said.
"From time to time we receive complaints from members of the public about speeding or other offences, but the complainant can give only the colour of the boat at best, which makes it difficult to take any follow-up action."
Otago Regional Council corporate services director Wayne Scott said the council was not looking at implementing similar regulations.
