The damage to Scenic Circle's Franz Josef hotel is thought to be in the millions, after the Waiho River tore through it after heavy rain last week.

Things are otherwise back to normal at the tourist hotspot, Managing Director Brendon Taylor said the hotel is like the new stop bank to the Waiho River.

"The hotel had all the glass panels blown out, a lot of the furniture was moved the whole length of the hotel so the force in the hotel must have been quite astronomical."

It's still unclear why the Waiho River burst its banks in such spectacular fashion in Franz Josef last week.

Close to 200 people had to be evacuated after the river tore through its stop bank, and carved a new path through the Scenic Circle Hotel.

Mr Taylor said the river, and stop bank have been through bigger weather events than the rain last Thursday, and they don't know what's changed.

"Our concern now is that something must have happened in that riverbed to change it's flow and to head it in that direction and we're trying to work out why it failed."

He said it's unclear whether the site is safe to return to.

Meanwhile the local mayor is warning of more floods to come, unless more money is put into building better infrastructure.

Westland District Mayor Mike Havill said the problem with the stop bank was identified previously but nothing was done to fix it.

"And it could have been a lot worse, so I think all of the parties concerned have got to get an active management plan for the river and start being proactive in preventing these things from happening."

But it's a problem that needs a national solution.

"The South Westland community don't have the resources to fix this on their own, they need help and the sooner central government recognise that and come to the party, the better off we'll all be."