From, "I've just been called into a last-minute meeting," to "I broke my kneecap on the way to our reservation," restaurant owners have heard it all.

Dimmi is Australia's largest online reservation service, hosting 4000 bookable Australian restaurants on its platform, making up about 40 per cent of Australia's restaurant market.

The blacklist figure, from Dimmi's annual No Show Report, revealed a sharp jump from the 3159 diners that had a mark against their name in March last year after the program commenced the previous month.

Restaurant diners find their name on the blacklist if they fail to show up at a restaurant booking, leaving them unable to book at that establishment for one year.

Data from the report suggests the penalty system is working, with a 25 per cent drop in restaurant no-shows recorded in the past 12 months, likely assisted by the Dimmi Payments system.

By storing customer credit card details, the system is designed to deter no-shows and take pre-payments for bookings.

It was introduced to address the estimated $75 million lost by the industry to no-shows every year.

Nelly Robinson, the owner of Nel Restaurant in Sydney's CBD, makes no apologies for charging $150 per person in a no-show booking, and attributes the policy to a reduction in no-show diners.

"We have been on board with this from day one," he said.

"If you don't turn up to a table, never mind the food and labour costs ... what about the people on the waitlist that have birthdays and celebrations and we can't fit them in? That's the thing that really gets me."

Mr Robinson estimates annual losses of $31,000 at his establishment if just two tables a week fail to show up.

"We had to charge somebody last week on Valentine's Day. This guy decided on the day he wouldn't come ... he said he would speak to his wife and ring back to reschedule, but he never called back, so we charged him," Mr Robinson said.

"If someone has a family bereavement or emergency, we will move the booking to a later date ... we have a heart. But if they choose to cancel completely they will be charged."

The top excuses Mr Robinson receives for booking cancellations at Nel Restaurant include "we've booked two restaurants as we couldn't decide and now we'd like to cancel ...", and, "I've just been called into a last-minute meeting."

He's also been told, "I'm at Wentworth Avenue in Parramatta" (Nel is on Wentworth Avenue in Sydney's CBD), and, "both my partner and I booked for the same night".

However the excuse that took the cake was, "I broke my kneecap on the way to our reservation" – which he said was in fact genuine.

Dimmi founder and chief executive Stevan Premutico described no-shows as "one of the biggest issues impacting the restaurant industry".

"We are doing our bit to try and eradicate no-shows completely by 2020."

Mr Premutico said the industry had shown an "overwhelmingly positive" response to the blacklist system.

"If someone is a no-show, they will be added to the list ... however, the restaurant can choose to override that," he said.

"Consumers in Australia don't typically 'no-show' with malice or bad intention. I just don't think they realise the impact it has."

Mr Premutico said that 24 hours' notice was common courtesy for patrons to cancel a restaurant, however four hours was still sufficient to enable an establishment to re-book a table.

In data shared exclusively with Fairfax Media last year, Dimmi reported that the most common no-shows in Australia lived in the postcodes 2000 (Sydney), 4217 (Surfers Paradise), 3000 (Melbourne) and 2010 (Darlinghurst/Surry Hills).

The gender split of no-show diners was 54 per cent female and 46 per cent male.

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