Air-conditioners in some substitute buses along Adelaide rail routes have been switched off because of the threat of Legionnaires disease, the Transport Workers' Union says.
Decommissioned buses are back on the roads during the closure of the Adelaide Railway Station and Belair, Tonsley and Noarlunga lines.
The union says the Government is putting passengers and drivers at risk by forcing them to endure temperatures above 40 degrees Celsius.
Ian Gonsalves from the union says the threat of Legionnaires is only in buses with evaporative systems, but says air-conditioners in other buses are also prone to failure.
Mr Gonsalves says the problem came to a head on Friday when Adelaide reached a top temperature of 45C.
"Some of the buses do have the overhead air conditioning which is refrigerated but in most cases they fail quite frequently," he said.
"It's happened numerous times... there were about nine or ten on that day.
"The bus gets up to around 50, 55 degrees and nobody can travel in those type of conditions.
"I think it's the responsibility of both the companies and the Government to ensure that the drivers and the travelling public are catered for and these certainly aren't in these conditions.
"Governments and the companies have a duty of care to make sure people travel on public transport in a safe and comfortable manner."
'Vastly better off'
Railway guards handed out water bottles to commuters on Friday but the State Opposition says that is not enough.
"It is the time of year when there are fewer commuters so it is probably right to do it in January while there are fewer commuters on our network," she said.
"But for instance are there more buses on order that could have been brought forward? Are there any other options that the could have explored in terms of how to reduce the level of heat stress for people?
"If there are old buses that had air-conditioning systems not working why not make sure they are working before you bring them back into service."
Ms Redmond made the comments at the same time as criticising the Government's attempt to make the transport system run more smoothly in the city by introducing priority bus lanes.
"The reality is that the vast majority of journeys will always be in private vehicles and we do need to make sure that we find the balance rather than trying, as the current Government seems to be doing, to keep cars out of the city," she said.
But Ms Redmond would not give details on the Opposition's plans for city traffic.
"We'll come out with a fully integrated transport policy before the election."
Transport Minister Patrick Conlon says the Opposition's criticism is hypocritical.
"Ms Redmond should be asked to explain just what's going to happen when cars get priority again," he said.
Mr Conlon also said passenger comfort on buses and trains has improved dramatically under the current Government.
"The drivers are vastly better off than they were when we came to Government until 2002 when half the fleet was air conditioned," he said.
"We don't want anyone to work in difficult conditions but it should be recognised that we have made dramatic improvements in public transport in the last few years and this closure itself is the final step in the complete rebuilding of our rail system."
The Government has agreed to meet with the union to discuss the situation.
Branch secretary Ray Wyatt says it is disappointing talks are only taking place now rather than before the substitute services were introduced.
"If we had been involved in the discussions, we could've pointed out from day one that the buses that they were going to use needed some work done to them," he said.
"I want to have some meaningful discussion about what can be done with the existing buses they're using.
"We all have a responsibility under the OH&S legislation to provide safe systems of work.
"I would strongly encourage Minister Conlon to come for a ride with me on a bus and bring some inspectors from SafeWork SA along for the journey with all their instruments and let's just go and see how hot it really is on a bus."
Mr Conlon dismissed that request as an 'empty stunt' but says he would be happy to meet with the union.
"I'll go out and ride my push bike in the heat if that helps anyone. I don't see how it will," he said.
"I don't understand where that would take people but if the Union wants to come and talk to me, we'll make an appointment."