UPDATED 10.57AM: They are less than a month old but new fuel lines at Kaikoura's dock have caused a minor diesel spill.

Marine Engineer Harry Pearson spotted pools of oil in the water near the seaside town's South Bay jetty.

Kaikoura Whale Watch general manager Kauahi Ngapora said they were fuelling a vessel in berth two, when they spotted diesel leaking in the unused berth next to it.

Environment Canterbury inspected the leak, which came from a faulty flange near a shut-off valve on a system installed and maintained by fuel provider McKeown Petroleum.

The fuel line was installed in the middle of December.

An Environment Canterbury spokesperson confirmed they spoke to Kaikoura Whale Watch, and aren’t taking the matter further.

Ngapora said the company was learning to better first responders.

Ngapora said they have made sure they have the proper gear, and are more informed to respond when situations arise.

He said they will be having discussions with McKeown Petroleum to ensure everyone learns from the issue.