A report by the French research organisation IRD says there is a heightened tsunami risk for the islands of Wallis and Futuna.
A team of scientists, including one from New Zealand's National Institute of Water and Atmospheric Research, studied the aftermath of last September's 8.0 earthquake which devastated parts of Samoa and Tonga.
The IRD report says although the wave caused no casualties in Futuna, a 4.3 metre high wave struck northern Futuna, pushing 72 metres inland.
It also noted that a drain made out of concrete was broken up on a stretch of 70 metres.
There were complaints in the islands that there was no warning when the tsunami struck.
