It was not so long ago that diners would receive a subtle, apologetic gesture from a waiter if their table needed to be re-set. But today, Australia's restaurant scene is fast turning into a tale of two sittings, the first of which can start as early as 5.30pm, in a bid to maximise their take.

Review forums and blogs are awash with comments from infuriated patrons who felt pressured to finish their meals. In some establishments, late arrivals and slow eaters have been denied dessert. Another common gripe is that while the restaurant stop watch starts from the designated booking time, rarely is it paused for mix-ups and below par service.

And according to new figures, one in five restaurants nationally will now only seat customers if they agree to vacate their table by a specific time.

Of those establishments that have implemented fixed-time dining, 50 per cent expect patrons to have settled their bill within 90 minutes, with a further 35 per cent looking to have moved diners on within two hours.

The statistics, compiled by online reservation website dimmi.com.au, also serve to highlight the demise of the traditional 7.30pm dinner booking, with diners now eating out earlier, more frequently – and over less time.

The award winning Balla, at Star Casino, has a 90-minute table policy for two guests and two-hour window for bigger bookings. "We are a fine dining restaurant ... but there are complaints from people hoping to stay longer, particularly if they're celebrating a special occasion," said a reservations spokesman.

Melbourne's Pei Modern offers customers two dinner time options, a pre-show time and after 8pm. Co-owner David Mackintosh said 90 per cent of patrons were "pretty relaxed" about the policy.

"If you want to linger, make a later booking: you can stay until midnight," he said.

"Restaurants are a business. If someone calls to make a reservation at 7pm but we need the table back by 8.15pm, we'd be very honest about it."

He believes the two-hour dining times are sufficient but added the restaurant tries to accommodate extra time if requested.

However Mackintosh said both customers and restaurants need to be flexible, adding that the policy was all about fairness.

"It's as much a response you try to accommodate as many people as possible. It goes both ways. It means a bit of flexibility."

Set dining times are a move away from the no-booking policy that swept Melbourne several years ago. Restaurants such as Mamasita and Chin Chin refused to take bookings, with hour-long waits for a table common.

Mejico, in Pitt Street, Sydney, offers two-hour online reservations for tables of up to six people – and 90-minute time slots for walk-in guests: "We're up front with our arrangements and generally people are fine with it. It works well," said host manager Jade Westwood.

According to Darran Smith, former general manager at Bondi Icebergs and Est, a 90-minute sitting should work effectively if customers have been greeted, seated and finished choosing from the menu, all within the initial 20 minutes. He believes entrees need to have typically come and gone in the following 20 minutes. If mains have been served and eaten within the next half hour, there is still a 10-minute window for dessert and five minutes for coffee, with time still left to settle the bill.

In Newtown, Hartsyard fulfills three, two-hour sittings for tables of two, from 5pm daily  with those windows extended by 30 minutes for tables of four. Manager Maddison Howes said: "There is additional flexibility when required. Our booking system allows for requests to extend, for things such as special occasions."

She said when tables do occasionally "run behind schedule", the restaurant was able to look after guests in its adjacent bar "which helps things flow".

But Erez Gordon, who does not have an "official" second sitting at Bishop Sessa in Surry Hills, described the strict "turning tables" policy as a "hiding to nothing" philosophy.

"If you take the industry as a whole, it is an absolute luxury," he said. "The restaurants that have sittings are, for the most part, doing so because demand exceeds supply ... and if that is the case, then of course you are justified in calling the shots. But you also have to be careful.

"If you become too stringent in the shots you call, you run the risk of disenfranchising customers."

According to Dimmi, the traditional 7pm-10pm dinner booking has dropped by 17 per cent nationally over the past four years while the typical pre-dinner slot of 5pm-7pm has jumped by 30 per cent over the same period.

However, Dimmi chief executive Stevan Premutico said those figures had been driven by changing dining patterns as much as forced early sittings and restaurants needing to "maximise revenues" to survive.

"There is definitely a trend across Australia towards earlier eating," he said. "Families are eating the pizza-style meal out more frequently, the corporates are finishing work and heading straight to dinner while solo diners have also increased dramatically."

Mr Gordon, meanwhile, said the "general attitude" among restaurateurs had only shifted because the economics nowadays had changed and "margins in products had become so minute. "It's not that restaurant owners are less hospitable than they once were," he said. "The reality is that having a table stay all night no longer generates enough profit to warrant opening the doors."

email: eduff@fairfax.com.au

with Alana Schetzer