A Tongan woman not only saved people's lives on the tsunami-battered island of Niuatoputapu but rescued their life savings as well, according to a report here on Saturday.

In an email forwarded to The New Zealand Herald newspaper, Mafi Lutui described how her survival instincts kicked in when the tsunami warning was issued following Wednesday's 8.0 magnitude earthquake.

Lutui, who manages the Tongan Development Bank in Hihifo, a tiny settlement on Niuatoputapu, said she packed her elderly mother-in-law and daughter into a van and was heading to the bank when she saw the first wave racing inland.

"All I can do was to go into reverse gear, put my foot to the floor, picked up all the people running on the road and headed towards the high ground," the newspaper quoted her as saying.

"The wave was about 10 metres behind us. I just kept praying and asked God for clarity and trying to keep the van in control."

After taking her passengers to safety, Lutui returned to see if she could help others but all she could see was devastation.

When she returned the following morning she found the bank safe poking up in the sea at low tide.

"I opened it and the money cash boxes were still intact (but) everything inside was soaking wet. I have locked all the money and it's in the (church) safe," she said.

In her email, Lutui indicated she had already ordered fresh stationery and hoped to reopen the bank next week.

Nine people were killed when the tsunami hit Niuatoputapu and 83 homes were destroyed, according to the Herald.