Germany's Auto Motor und Sport reports rumours that world champion team Red Bull's boss Christian Horner had floated the idea of delaying for a week the start of winter testing late this month.
"Nothing is being moved," Mercedes team chairman Lauda insisted. "The plans are going ahead for late January.
"The task of big for everybody."
The report said the German squad is currently testing its new V6 engine, energy recovery technology, gearbox and cooling systems in a hybrid chassis on the test bench.
Lauda admitted that cooling the 2014 package is one of the greatest challenges.
"We are constantly learning new things," he said. "Suddenly you are managing things like water pressure and intercooling.
"Oil and water must be in a precise temperature window," added Lauda. "Once you go just a few degrees above a certain limit, everything stops (working)."
The triple world champion said he sympathises with the customer teams, who unlike the full works teams like Mercedes and Ferrari are unable to do "any comparison testing".
"They are doing their cooling (development) only on the basis of information provided by the engine partner," said Lauda.
And he thinks Mercedes and Renault, each with three non-works customer teams, have a slight advantage over Ferrari, who are only supplying customer engines to Sauber and Marussia in 2014.
"Four teams is four sources of information," said Lauda. "Everyone is having their individual problems, so we can learn faster and respond sooner."