Mr Alexander said central and local governments would need to work together on the issue.
"We need some high-level guiding principles about how our society and various agencies manage these issues going forward," he said. "It is our view that climate change is a significant part of that, both in terms of storms and sea level rise."
The Insurance Council chief executive Tim Grafton last month sounded a warning on climate change, saying that by 2050 about one million older Kiwis will be living in areas vulnerable to severe flooding, coastal storm surges, land slips and wind storms.
Mr Alexander made his comments in reply to a question from Green MP Eugenie Sage, and while appearing before the local government and environment committee at Parliament.
Collectively, local authorities are responsible for more than $100 billion of community assets, providing essential everyday services.
The focus on the meeting was a recent report from the Office of the Auditor-General, which flagged concerns about whether councils and authorities were adequately investing in roads and the "three waters" - water supply, wastewater and storm water services.
The report said most authorities decision-making around infrastructure services was adequate for short to medium-term planning, but it found concerns beyond that.
There is a huge gulf between the depreciation expense claimed by councils in their annual financial reporting, and the capital expenditure on renewing those assets budgeted for in their 10-year plans.
On average the latter is only two-thirds of the former, resulting in a cumulative shortfall by early next decade of $6 billion to $7 billion.
Chair of the committee and National's Coromandel MP Scott Simpson asked the Local Government NZ representatives if his summation of the report was correct.
"Essentially it's a report that says, 'Out of sight, out of mind' - the infrastructure that occurs underground in terms of sewerage and potable water and storm water is, because it's out of sight, largely off the radar.
"And because it's expensive it's the sort of decision that elected councillors may sometimes put in the deferred expenditure area, particularly when there is pressure on rates and other areas that are perhaps more visible?"
Lawrence Yule, president of Local Government NZ and Mayor of Hastings District Council, said that was "absolutely a dynamic that can be at play in some councils".
A report that examined spending and infrastructure in the "three waters" would be completed in the coming months, and it would give a much clearer idea of what could be going on and how to respond to the Auditor-General findings, Mr Yule said.
"We think an appropriate issue has been identified, we are very close to getting a far better understanding of the three waters, which is the biggest area that is unknown."
Mr Yule said the overall picture could include pressure from central Government to keep rates rises low and the potential of new technology to reduce the required level of spending on infrastructure.
His vice-president Brendan Duffy, Mayor of Horowhenua District Council, called for more central Government help for smaller councils that could not afford technology that could lead to huge savings, one example being cameras that go down pipes to assess for wear-and-tear.
"I can give you a brilliant example where a council was told a pipe was out-of-date and had to be replaced. They spent $8 million replacing it, an engineer pulled that pipe out of the ground, sent it away for x-ray, it had 22 years of life in it," Mr Duffy said.
