The Daily Post said the flood struck as the area has been trying to recover from last month's cyclone Hola while trying to cope with ash fall from Manaro volcano.
There is no information about any casualties.
The government has already sent emergency food supplies to the island and approved $US400,000 to be spent on short term food and supplies in the disaster zones of west and south Ambae.
The island's MP Alickson Vira had appealed to the government to declare the whole island a disaster zone and to identify evacuation centres for when volcanic eruption increases to level 3.
Mr Vira said victims didn't know where to go for safety from worsening ash fall.