You've almost certainly encountered it, and if you haven't, it looks like you're bound to soon.

Diners are increasingly being asked to fork out extra for brunch, lunch or an afternoon cocktail on Sundays.

Weekend and public holiday surcharges are legal and, according to the Restaurants and Catering Association, an important part of helping hospitality businesses break even.

They're also probably going to become more common — and steeper — with produce prices soaring and hospitality wages having increased as of October 1.

"Otherwise, [restaurants and cafes] might as well not open, and I think we all love to have a coffee and go out for brunch on a weekend."

Some restaurants will slap you with a Saturday surcharge, but most will confine the surcharge to Sundays and public holidays.

What are the rules around the surcharges?

The Australian Competition and Consumer Commission – which enforces fair trading laws in the country – allows restaurants and cafes to charge a surcharge on weekends and public holidays.

Queensland's Office of Fair Trading tells businesses they don't need to produce separate menus for surcharge days and can simply display the increase as a percentage on their menu "as long as you display it prominently, clearly and transparently".

According the ACCC businesses shouldn't impose a surcharge unless they're facing elevated costs on that particular day.

"Businesses should not mislead consumers on the price of goods or services, including any unavoidable or pre-selected additional charges that might apply to the transaction," a spokeswoman said.

Customers who believe they've been hit with undisclosed surcharges can make a complaint with their local fair trading or consumer affairs agency, the ACCC spokeswoman said.

Typically these charges are about 10 per cent, according to the Chamber of Commerce and Industry Queensland (CCIQ).

"What we might be seeing is a movement in the amount," CCIQ workplace relations general manager Joanna Minchinton said.

So where does the money go?

Mostly the surcharge helps to cover staffing costs, Ms Minchinton said.

"For a permanent employee, who's classified as food and beverage grade two — so they serve drinks, they serve food — the Monday to Friday rate of pay is $22.77 per hour," she said.

"And then when you've got a public holiday … it moves to $51.23 per hour."

Weekend penalty rates are an important part of hospitality work, but it means that businesses face extra costs on weekends and public holidays.

"We really want to make sure that our industry is paying people properly," Ms Clarke said.

"We want to make sure that we are a career and we're looked at to be a reputable industry to work in.

The Restaurants and Catering Association conducted a survey of business owners at the end of 2021, asking if they ever failed to pay themselves at an appropriate wage based off the standard for their industry.

"Over 60 per cent either underpaid themselves to make ends meet, regularly or significantly or just do not pay themselves at all to make ends meet," Ms Clarke said.

According to the CCIQ, restaurant and cafe owners have an average profit margin of less than 10 per cent of their revenue.

"The surcharge has a benefit in helping the business to stay open to provide the social outings that we all need on weekends and public holidays," Ms Minchinton said.

"So that's where I guess your surcharges will help the business to stay open."

Is it necessary?

Both the CCIQ and the Restaurant and Catering Association say so.

It helps a business account for penalty rates – that more than double an average wage bill on public holidays – as well rising ingredients costs.

"These businesses are key for the socialisation for community and for connection, and surcharges enable those businesses to stay open, to stay operating and to stay alive," Ms Minchinton said.