The policy currently put the hours of sale at 7am-10pm but Dr Mills and others have advocated for 9am-9pm hours, in line with Auckland Council.
Mr Harford said Whangarei should keep to the national default hours of 7am-11pm. The legislation said hours may be changed by councils if there was proof of a local issue, he said.
"At this stage, we don't think there is clear evidence of a local issue [in Whangarei]."
If you restricted hours to the point Dr Mills wanted, it would negatively impact the economy, Mr Harford said. People who drank responsibly would change their shopping habits to only shop when alcohol could be sold. As a result, supermarkets might change their opening hours or employ less people early in the morning or late at night.
"I think there's certainly a number of people in the community that don't use alcohol appropriately," Mr Harford said.
However, he said he did not think a change of hours would lessen problem drinking.
"They are just going to buy it at different times," he said. "There's a real question about how alcohol-related harm is going to be measured," he said.