The overhauled ACTION timetable was due to take effect on Monday, October 12 to improve performance and introduce the mandatory break for drivers.

Territory and Municipal Services Minister Shane Rattenbury said the changes would be delayed until some time in early 2016, conceding the error was embarrassing.

He said the government had decided to pull the proposed changes as soon as the problem emerged. ACTION has about 17 buses below what it would require to run the timetable.

"The 10 minute break essentially takes some drivers out of action. They finish a run, drive to a rest point, have their 10 minute rest, drive back and start again.

"The software counted what might be called ghost buses, because it didn't take into account of the fact the bus is with the driver when they take that break. The software wasn't geared to it... so it all seemed fine," he said.

The error would have seen about 50 services each day not run.

The revised timetable was developed in response to Fair Work Australia's requirement for bus drivers working for more than three hours get a 10-minute break. The government is working to improve performance of Canberra buses and wanted to ensure services were matched with demand.

The changes were based on MyWay travel card data, customer feedback and GPS tracking of buses.

Mr Rattenbury said a new weekend timetable will begin on time from Saturday, October 17, as planned, and include the 10-minute driver breaks.

"It is embarrassing, there's no doubt about it," he said. "Everyone in the organisation is deeply disappointed. The staff at ACTION have been working really hard on these changes and when they had to come and tell me about it, they looked very uncomfortable.

"We've been working very hard to make improvements. We've pushed on-time running up from 68 per cent two years ago to 79 per cent now, and this timetable was designed to take it to the next step."

Passengers will be informed about the withdrawal of the timetable changes through advertising and on the ACTION website.

"We're telling people now, four or five weeks ahead. The current timetable will keep working and so in that sense, it will keep going," Mr Rattenbury said.

"Basically we have to start again, and it takes a long time to design the whole network."

Opposition transport spokesman Alistair Coe said the changes represented a serious error.

"This blunder is not good enough from Shane Rattenbury. He needs to focus more on ACTION, rather than gazing ahead at a light rail project which will service only a fraction of those who currently utilise ACTION right across Canberra," Mr Coe said.

For more information, visit www.action.act.gov.au