Kate Morrison, Commerce Commission general manager of competition, said attempts to fix prices in any industry were serious.
"Price fixing harms competition and can lead to consumers paying higher prices.
"We credit Ansell Flooring Limited's competitor for recognising the anti-competitive behaviour and reporting it to the commission," Morrison said.
She said because Ansell Flooring had cooperated with the commission's investigation, a warning had been deemed appropriate.
"However, we won't rule out stronger enforcement action in the future if there are further allegations of anti-competitive behaviour by Ansell Flooring Limited."
Under the Commerce Act, it is illegal to enter into any contract, arrangement or understanding which leads to fixing the price of goods or services.
Penalties for breaching the act can be as high as $10 million for companies and $500,000 for individuals.