Then, on Sunday, around one-third of the 133,000 subscribers to the service, provided by Weatherzone, received advice of the day's heavy downpour after the two storms had passed over.

Council will pay Weatherzone $247,441 over the next two years to provide the service.

Weatherzone is owned by Fairfax Media, publisher of this website.

Two weeks ago, Council's Civic Cabinet also bought forward $73,000 to update the separate Floodwise Information System, which provides flood mapping of each residential and commercial block in the city.

At last Tuesday's council meeting, Labor questioned Brisbane's administration about wrong texts from the Weatherzone service.

Labor councillor Shayne Sutton said she received several wrong text messages from Weatherzone "several weeks ago".

"Some of these text messages for a number of Brisbane suburbs said, 'You're going to be flooded within half an hour', and then three hours later it said, 'Disregard that message'," Cr Sutton said.

"Obviously there's a problem there."

However, council's economic development committee chair Krista Adams told last week's meeting that 21 erroneous texts about flooding were triggered by a "gauge error in the Rocky (Waterholes) Creek system".

"There was a blockage in the sensor tube," Cr Adams told councillors.

"So that's why it was withdrawn as soon as they found that there was an incorrect reading on the gauge."

The problem was identified because it was a fine day and not raining when the flooding alarms were issued.

Cr Adams said the errors had been raised with Weatherzone.

"Weatherzone is still working on all of that and making sure that any of those glitches in their messaging systems can be tidied up," she said.

"But I still have to say it's better to get too many (warnings) than not get enough."

At Tuesday's final council meeting for the year. Labor councillors will heavily question Lord Mayor Graham Quirk and senior councillors about the system.

After Monday's Civic Cabinet meeting, Cr Quirk told reporters the current service was "unacceptable" and said the priority was to get the system operating accurately and quickly.

"We are in storm season and we want to get this sorted as quickly as possible," Cr Quirk said.

Cr Quirk said a trial run, "a few days earlier" had worked successfully.

"So clearly (Sunday's delays) are unacceptable,"Cr Quirk said.

"And we are going to drill down until we find out exactly what happened."

Cr Quirk said there had not been other problems with the Weatherzone system itself.

He said he had simply looked at the storm clouds gathering in the sky after a very hot day to identify a storm was underway.

"So there are other 'sources' available," he said.

On Monday night Fairfax Media was told by a mayoral spokesman that Weatherzone had identified the problem and steps were being taken to remedy the situation.

Weatherzone packages weather data based on information from the Bureau of Meteorology.

A spokesman did not reply directly to questions from Fairfax Media on Monday night.

Meanwhile, council will on Tuesday launch a public campaign to ask its residents what new infrastructure they believe the city needs as its population increases by more than 400,000 over the next 25 years.

A new Local Government Infrastructure Plan will replace a list of projects put together in 2014.

Public consultation on the new plan begins in mid-2017.

It will help the council identify new roads, pathways, ferry terminals, bridges, public parks, land for community facilities and stormwater infrastructure to cope with the extra residents.

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