Water will be released from Wivenhoe Dam in anticipation of up to 300 millimetres of rain being dumped on southeast Queensland over the weekend.
However, the order to release the water did not come from Seqwater.
Instead it came from Energy and Water Supply Minister Mark McArdle who, along with Premier Campbell Newman, told reporters it was designed to reassure people who were concerned about river flooding.
Mr Newman said Seqwater "fully supported" the decision and 41,000 litres would be released from Wivenhoe Dam over 24 hours from Friday afternoon.
The Bureau of Meteorology is forecasting 200-300 millimetres to fall on Brisbane, the Gold Coast and the Sunshine Coast on Saturday and Sunday.
The Wivenhoe Dam's water supply capacity is currently at about 91 per cent.
Once it reaches 100 per cent, it can hold another 100 per cent of water for flood mitigation.
In January 2011 the Wivenhoe Dam reached about 170 per cent after months of sustained rain.
During the flood dam releases peaked at 645,000 megalitres.
This weekend's release of about 41,000 megalitres represents about 1.8 per cent of Wivenhoe Dam's total capacity.
On Thursday Seqwater engineers advised the government there was no need for a water release.
When directly asked if its advice had changed, Mr Newman refused to answer.
"The situation is changed, the BOM forecast is changed, the rainfall estimates are much higher now from the BOM," he said.
"And as a result there has been, obviously, a re-evaluation.
"I'm quite happy to say, as Premier, a former lord mayor ... we're not just sitting here waiting to be given advice, we'll actively consider the matter."
Mr Newman said the real concern in Brisbane over the weekend would be suburban flooding, and stressed the importance of avoiding a "tragedy" by making sure children did not play in stormwater drains or swollen creeks.
Mr Newman's warning came as Police Minister Jack Dempsey prepared to tour central Queensland towns which had been lashed by ex-tropical cyclone Oswald.
Mr Dempsey slammed people who ignored warnings and were caught up in swift water.
"If it's flooded, forget it," Mr Dempsey said.
"We have seen some ridiculous situations throughout Queensland in the last 24 hours where people have unnecessarily put emergency services workers' lives at risk just simply for a little bit of tomfoolery."