"The proposal is simply an increase in the rates paid by hotels and motels - a very substantial increase. The amount will vary depending on the capital value of the property - nothing to do with the number of rooms or how much is charged for them. So the impact will be different on every business," said Roberts.
He said it was wrong for Goff to assume the cost would be passed on to guests, saying hotel do not add a line for "electricity" when power bills go up.
"It's a competitive market and hotels and motels are competing with airbnb properties which don't have to pay this extra rate. It's going to make life less profitable for hotels, and discourage investors from building new ones," he said.
Roberts said there was a case for a properly designed levy that funds tourism infrastructure - but no justification for an unfair rates burden on one section of ratepayers to fund marketing, which benefits all of Auckland.
In Goff's first mayoral proposal, which contains the visitor levy, he said council staff would work with the tourism and accommodation sector on the design of the levy.
"Ateed (Auckland Tourism, Events and Economic Development) has been exploring with the commercial accommodation sector the available options for indirectly funding some of Ateed's visitor-related expenditure from visitors rather than Auckland ratepayers," Goff said.
The charge would replace ratepayer-funded spending to attract visitors and support major events.
Goff will present his mayoral proposal to the finance and performance committee today.