A volunteer firefighter will give evidence at Queensland's flood inquiry in Toowoomba on the Darling Downs today, saying he was gagged from speaking out about the management of the disaster.

Danny McGuire was in Grantham in the Lockyer Valley the day the torrent of water swept more than a dozen people, including his own wife and two of his children, to their deaths.

Mr McGuire has told ABC Radio's AM program he warned authorities to evacuate Grantham two days before the disaster and that no-one listened.

He says the fire service ordered him to hide in a motel for nearly six weeks after the flooding and not speak to anyone.

Mr McGuire says he cannot wait to testify at the flood inquiry today about how he was silenced by the fire service.

"We were hidden in a motel in Toowoomba and my group officer was told to look after me and make sure I didn't get in contact with anyone because we actually asked to have the place evacuated two nights before," he said.

"It should have been done and they are trying to hit me up by saying I broke rules and regulations by driving fire trucks in the water to save people, but I did save lives."

Inquiry commissioner Justice Cate Holmes raised concerns with State Government Counsel at yesterday's hearing in Toowoomba.

Justice Holmes says staff and volunteers were having trouble speaking freely to the Commission because they were being asked to consider strict laws on public servants speaking out.

The inquiry heard Government barristers had turned up at an interview organised by Commission staff.

It is believed employees have also been told to first consider the law on public servants speaking out.

She says it may be unintentional but it seems at worst to be having a chilling effect on their willingness to speak frankly.

Justice Holmes says it would also be helpful if the Government ensured staff were not prejudiced for giving evidence to the inquiry.

Last night, the Queensland Government responded to the commissioner's concerns, with Premier Anna Bligh saying every public servant should assist the inquiry in every way possible.

It was backed up by a memo from Ms Bligh's director-general to all public servants, as well as State Emergency Service (SES) and rural fire volunteers.

Ms Bligh says Crown Law advice is available, but not compulsory.

"Any public servant who is appearing before the inquiry, who wants to be represented by Crown Law or the legal section of their department is entitled to that legal assistance, but they are not required to seek it," she said.

'Shut down'

Mr McGuire has lived and worked in Grantham for almost four years and as a rural firefighter he helped many, but his greatest test was during January's flood.

With his wife and three children on board his fire service truck, he drove through floodwaters to help the stranded but the vehicle was overwhelmed by a wall of water.

Only he and son Zach survived.

Mr McGuire says he told his superiors the water was rising fast in Grantham and it was getting dangerous.

"We actually asked to have the place evacuated two nights before," he said.

"We asked to evacuate the whole bottom-end of Grantham until the rain starting easing up on us and we got told stand down, we were only rural firefighters - it was up to the SES.

"It was their call and that's why the fire service had us in lockdown for so long because they were worried this would get out to the media."

He says authorities were worried about what he would say.

"Just that it should have been done like we asked," he said.

He says he has not spoken out as he was "shut down".

"Every time I go to talk to someone, I get pressure against me and I was actually told to stay away from a couple of meetings," he said.

He also says it is more than just him who has been encouraged not to say anything.

"There's a lot more people," Mr McGuire said.

Reprisal fears

Gerard Keogh, who has been volunteering in the Lockyer Valley since the disaster, agrees with Mr McGuire and made a written submission to the inquiry.

"I've been there since January helping the people and I've spoken to a lot of the people and become friends with a lot of the people and a lot of them are afraid they don't want to talk, for fear of reprisals from the Government and their superiors," he said.

"They've got jobs families and children to look after.

"Maybe that they invite the public servants in to meet with the commissioner on a one-on-one basis, maybe with a guarantee they won't face any reprisals."

Mr McGuire has appealed for people to come forward and give evidence so the community can prepare should the worst happen again.

He says he has been asked to resign from the Rural Fire Service for driving through floodwaters to save people.

"The guys in the Blue Care bus would have ended up dying - there was eight on that," he said.

"You would have lost a couple of police cars in Grantham, maybe a few other cars and a couple of other people."

'Stretched' resources

The Mayor of the Lockyer Valley Regional Council, Steve Jones, is also due to appear today, along with representatives from the Queensland Fire and Rescue Service.

In his written submission, Mr Jones says flooding on Boxing Day was the first of what was to be a series of events that would occur over the next two weeks.

He says long hours and constant pressure had taken their toll on the disaster management team by the time of the catastrophic floods on January 10.

He says authorities coped, but there was a general feeling resources were becoming "stretched".

"The disaster created by the events of the 10th of January tested existing communications to the limit," he said in his submission.

Mr Jones says the situation worsened when mains power was lost in the days afterward and back-up battery power was exhausted.

Flood survivor

Peter Souter is another of several flood survivors due to appear at the hearings today.

He operates a camp site on the banks of Murphys Creek.

In his written submission to the inquiry, he describes seeing extremely heavy rain on January 10.

"I recall looking through the window and seeing a wave of water break in the distance," Mr Souter said in his submission.

He describes the force of the water ripping out all the trees in its path and how at one point the water rose 10 metres within 10 minutes.

- Reporting by Matt Wordsworth, Francis Tapim, Chris O'Brien and Maria Hatzakis