However, the online retailer founded by entrepreneur and television personality Naomi Simson has egg on its face after it paid penalties totalling $43,200 for alleged breaches of consumer laws.

The penalties follow four infringement notices issued by the Australian Competition and Consumer Commission, which alleged Red Balloon charged four consumers excessive surcharges on payments they made by MasterCard and Visa credit and debit cards.

"Red Balloon was charging these customers more than allowed under the law prohibiting excessive payment surcharges on card transactions," said ACCC deputy chairman Dr Michael Schaper.

"This provides that businesses can only pass on to customers what it costs to accept the payment, including fees such as merchant service fees, and terminal rental and maintenance fees."

Red Balloon cooperated with the ACCC's investigation and has lowered its payment surcharges to the correct amounts.

The ban on excessive surcharges has applied to large businesses such as Red Balloon for more than 12 months. For other Australian businesses, the new law has been in force since September 1 this year.

"If a business wants to impose a payment surcharge on card transactions, that business is responsible for ascertaining the cost of acceptance of the payment before imposing the surcharge onto customers," Dr Schaper said.

"If a business is unsure what the cost of acceptance is for a particular payment method, it should contact its financial institution to obtain a copy of its annual statement."

Dr Schaper said any business, large or small, charging excessive surcharges on card transactions, whether intentional or not, risked ACCC enforcement action.

Red Balloon, which has 78 employees, was founded in 2001 by Ms Simson, who appears on television's Shark Tank.

She said the excessive surcharges "was absolutely not intentional" and the problem was fixed as soon as it was identified.

She attributed the problem to a misunderstanding of the new laws: "We consider ourselves as a small business but actually by definition we're a large business."

Ms Simson also said it was costly and time-consuming for businesses to comply with laws and regulations that can be different in each state and territory of Australia.

She said there were hundreds of debit and credit cards that may charge different surcharges on transactions.

"Staying up-to-date is really, really difficult," she said. "So you do have to make sure you have the right advisers around you.

"Compliance is expensive and hard for small business."