Entrepreneurial Maccas fans have jumped on the frenzy over Big Mac Special Sauce being bottled and started flogging portion sized tubs of the condiment online.

A 25ml sized tub is now selling on Ebay for $7.95, following McDonald's announcement that one bottle of its trademark yellow burger sauce will go on sale in Australia.

But as any real Big Mac lover will know, you can already walk into the chain's fast food outlets across Australia and buy an open portion of the sauce for just 50 cents.

Each of the country's 920 outlets have also now been given 600 small sealed tubs, weighing in at just under an ounce each, to sell until supplies run out.

McDonald's this week made the decision to release the sauce outside of a Big Mac order to raise funds for its charity arm in Australia.

The first fancy bottle officially placed on Ebay has already reached $23,1000 AU in bids, at the time of publishing this article.

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A 25ml sized tub of Big Mac sauce is now selling on Ebay for $7.95, following McDonald's announcement that bottles of the trademark sauce will go on sale for the first time ever

Entrepreneurial Maccas fans have jumped on the frenzy over Big Mac Special Sauce being bottled and are selling small portion sized tubs on Ebay for inflated prices

'Improves everything': An eBay listing for the sauce suggests it is the ultimate condiment

But for those who don't have a spare twenty grand and like to buy in bulk, a whole box containing 200 tubs can now be snapped up for a bid over $49 on the same site.

The box is being advertised as located at Mansfield Park, South Australia but can be posted 'worldwide'.

The box's seller wrote: 'For sale I have a carton of 200 x 25ml Limited edition McDonald's Big Mac sauce tubs. The carton is sealed (as pictured). Get in quick to secure your chance of history! ** can ship international if required ** Flat Rate $50.00. Please contact me to arrange.'

Other sellers, who also appear to be based in Australia, are offering the tubs in smaller batches.

A whole box containing 200 tubs of Big Mac sauce can now be snapped up for a bid over $49 on Ebay

Saucy: An online auction of the chain's first sale-able bottle of Big Mac sauce have attracted bids of $23,000

McDonald's official eBay listing touts the exclusivity of the product, and says it will overshadow all other condiments.

It says: 'This bottle is #1 of only 200 being produced worldwide, and they won't be sold in restaurants. That makes it rarer than a spot on Bondi beach on New Years Day.

'So slide the mustard, mayo and tomato sauce to the back of the fridge – because everything tastes better when it tastes like the Big Mac.'

The proceeds of the sale will go to Ronald McDonald House Charities, which help ill children and their families.

Australia only: The sauce, which McDonald's said lots of people have asked about, will also be available to high online bidders

The contents of Big Mac sauce have long been touted as a secret. But in 2012, the chain's executive chef in Canada made a video showing people how to whip up their own.

According to the clip, which has 4million views on YouTube, the ingredients are mayonnaise, sweet pickle relish, yellow mustard, white wine vinegar, garlic powder, onion powder and paprika.

The auction comes as McDonald's has been struggling with sliding profits in recent months.

Changing tastes - which see the likes of Chipotle and Shake Shack surge in popularity - have hit the retailer's customer base. Food safety scares in Asia have also harmed the bottom line.

Since the slump, McDonald's has responded with a number of feel-good initiatives, such as this charity push.

In the United States, the chain is offering some customers free food if they smile, dance or hug at the checkout during February, a promotion it announced in its Super Bowl ad.