Prof Kurt Krause, director of the Webster Centre for Infectious Diseases, was commenting on the Food and Drug Administration's decision to ban 19 active ingredients found in household antibacterial products, including triclosan.
The FDA cited lack of effectiveness and suggested the products could be causing harm.
Triclosan is also found in other consumer products.
Prof Krause said triclosan had been implicated in antibiotic resistance and there were fears it could disrupt the endocrine system in humans.
Prof Krause said he had been concerned to see it added to items such as children's toys as an antibacterial agent, and the new ruling did nothing to change that.
Its increasing use had been like a ''tidal wave'', Prof Krause said.
''The way that this triclosan wave got going and almost could not be opposed really took me by surprise.
''Whenever you introduce something that kills some bacteria, the bacteria get more resistant, and it's like an arms race.''
He supported the FDA decision, and said New Zealand should consider following suit.
Prof Krause said medical and community attitudes to bacteria were changing because of the antibiotic resistance problem and because of awareness of the ''microbiome''.
''There are more bacterial cells living in our body than human cells.''
''We're host to thousands of different species of bacteria and billions of bacterial cells.
''It's much better to kind of get along; there's a huge move to have a healthy microbiome.''
Dr Krause supports the use of antibacterial agents in hospitals ''because you're targeting a specific bacteria in a specific place''.
In New Zealand, the chemicals are regulated by the Environmental Protection Authority, which said it was aware of the ruling and was not in a position to comment.
''We will be looking at it to determine whether there is any significant new information and assess its relevance to New Zealand.''
Cosmetic Toiletry and Fragrance Association of New Zealand executive director Garth Wyllie said its member companies had been moving away from triclosan ''for some time''.
''[However] there are still a number in the market. If you go on any supermarket shelves you'll see some still out there.''
Mr Wyllie expected New Zealand to follow suit at some point. The US ban might make that happen more quickly than expected, Mr Wyllie said.