Britain's Health Protection Agency (HPA) has tried to calm safety fears over energy-saving light bulbs.
The German Federal Environment Agency (UBA) warned pregnant mothers and children to stay away from burst bulbs after initial tests revealed that mercury pollution around smashed lights can be up to 20 times higher than the safe guideline for an indoor area.
But the HPA, which has carried out its own tests, said mercury vapours from a broken eco-bulb "do not pose a significant threat to public health".
The European Union is phasing out traditional incandescent bulbs to replace them with energy saving Compact Fluorescent Lamps (CFLs), which are up to 80 per cent more efficient and can save £6 a year in bills.
The UBA carried out "worst case" tests on two energy-saving lamps without protective casings which were broken while hot and in operation one metre above the floor. Its president Jochen Flasbarth said: "The presence of mercury is the downside to energy-saving lamps. We need a lamp technology that can prevent mercury pollution soon.
"The positive and necessary energy savings of up to 80 per cent as compared to light bulbs must go hand in hand with a safe product that poses no risks to health."
Mr Flasbarth advised consumers to use plastic-coated lamps, which protect against breakage, in children's rooms, schools and sports areas, and called for more such bulbs to be made available on the market. He said the lamps should be designed to operate with the least amount of mercury possible and believes lamp technology will soon do without mercury altogether.
The HPA said mercury exposure from a broken bulb was likely to be very small, and much lower than from some types of thermometer and barometers.
After tests last year, Professor Virginia Murray, consultant medical toxicologist, said: "Compact fluorescent lightbulbs contain a tiny amount of mercury - roughly enough to cover the tip of a ball point pen. A small proportion of this could be released into a room if the bulb is broken, but this does not pose a health risk to anyone immediately exposed.
"As a precautionary measure, the HPA advise that the room should be ventilated and the bulb cleaned up and disposed of properly."
In the case of a broken bulb, the agency advised people to wipe the area with a damp cloth, collect residual debris using sticky tape, and place everything in two sealed plastic bags.
CFLs, whether broken or intact, should be treated as hazardous waste and local authorities have information on where to dispose of them.
A Department for Environment, Food and Rural Affairs (Defra) spokeswoman said: "Guidance from the Health Protection Agency makes it clear that the mercury contained in low-energy bulbs does not pose a health risk to anyone immediately exposed, should one be broken."
Watts the difference: the end of the 100 Watt light bulb
Silicon Valley looks to LED lighting
Lighting pioneers wish the CFL a happy 25th birthday
UK transition to energy saving light bulbs is rocky