Paul Clancy says chamber members “recognise that it protects the health and safety of their own staff, as well as customers”.
A chamber survey of its members last week found 83% of 171 businesses who responded backed the mandatory wearing of face coverings.
“The reality is that we will all have to make some changes to how we live, work, shop and socialise,” said Mr Clancy.
“And if the wearing of face coverings is mandatory, it will help promote more of a cultural change in the acceptability of wearing face coverings.
He added: “This has been an enormous time of change.
“But we must all play our part to protect public health, keep the spread of coronavirus to a minimum and avoid a second wave which will be catastrophic for many businesses.”
Public health, and the health of shoppers and shop staff, must be the “number one priority of retailers”, he said.