A Waikato man has decided to build an ark after receiving a letter from the council telling him his home was at risk of flooding, despite it being built on high ground.

Zane Ratcliffe, who lives in a suburb overlooking Hamilton, is among 28,000 homeowners in the city who have received letters from the council warning them their homes are in potential flood areas.

Mr Ratcliffe has dismissed the warning as a joke and has started building an ark.

"The street's called Gavin Heights, it's called that because it's high," he told the Waikato Times.

"So I figure if my house gets flooded then the rest of Hamilton will be totalled."

The letter from the council followed a $471,000 flood modelling project, however, the letter doesn't give any information about the specific flood risk or where the flood waters might rise from.

Mr Ratcliffe is concerned about what impact the flood risk label might have on the value of his property.

He says a council official has promised to review his case after he asked her to pay for any losses he could incur.

The council should be sure of its facts before it threatened people's livelihoods with broad claims, Mr Ratcliffe says.