Australian burrito chain Mad Mex has seen a successful uptake on its month-long Cinco de Mayo Big Burrito challenge, reporting over 2000 of the one-kilogram burritos sold at its nine outlets in NSW, Queensland and Victoria.

"It's fantastic to see how popular and how much excitement the Big Burrito Challenge has created with our customers," says Mad Mex Founder, Clovis Young.

"The level of activity on twitter, facebook pages, and in blogs has exceeded our expectation and certainly the sheer number of customers that have taken the challenge has exceeded our forecasts.

The challengers have made this competition their own, some competing against their mates to finish it first while others have refused to give up until they'd polished it off, no matter how long it took.

And it's not just the guys successfully rising to the challenge, we've seen a lot of young women come in and match the guys in their efforts."

Since the Big Burrito first appeared on menu boards at the beginning of the month, the brand's Facebook page has rapidly filled with photos of customers' Big Burrito feats in an online Hall of Fame while Twitter has been awash with Tweeters bragging of their accomplishments in finishing it.

Filled with double the standard portion, wrapped in two tortillas and weighing in at a hefty one kilogram, the Big Burrito temporary promotion has tapped the same food-endurance frenzy as KFC's Double burger.

The company said the Big Burrito was conceived as an "engaging and fun way to mark the Cinco de Mayo holiday on 5 May, offering customers a challenge with the same 2-to-1 odds that a Mexican army overcame in a historic battle that the holiday commemorates".

Demand in-store for the Big Burrito has seen eager diners happily queue to take their shot at the Big Burrito, one Tweeter last week posting a photo of the line for Sydney's Circular Quay store snaking half the length of the shopping centre.

As well have having their photos posted in the online Hall of Fame, successful challengers also receive a special-edition t-shirt providing "bragging rights".

Mad Mex currently operates seven outlets in NSW, one in Melbourne and one in Brisbane.