Scientists are battling to save Taiwan's ancient "Queen's Head" rock from erosion -- but the island is split over whether technology should be used to preserve the precarious natural masterpiece.

More than three million people visit the coastal landmark in northern Yehliu each year, named for its supposed likeness to England's Queen Elizabeth I.

The tilting "head" is an imposing sweep of sandstone which mushrooms out of a slender stem.

Honed by sea water and strong winds the head tapers up to a point, likened to the piled-up curls of the eponymous royal.

But at 4,000 years old, exposure to the elements means it may soon topple.

"The neck may become too thin to support the head and might break off within the next five to 10 years, if nothing is done," warns Hsieh Kuo-huang, a professor at the Institute of Polymer Science and Engineering at National Taiwan University.

"Any strong earthquakes or severe typhoons may bring down the rock formation," said Hsieh, who is one of the scientists studying how to preserve the rock.

Researchers say the circumference of the neck is shrinking by 1.5cm-1.6cm (0.6 inches) each year, making it harder to support the 1.3-tonne head.

"The shape of 'Queen's Head' today looks most elegant," says Helena Tang of Neo-Space International Inc which manages the geopark where the rock stands.

"But sadly, there's not much time left."

Hsieh's team have been experimenting with ways to save the formation, which stands eight metres tall from its base.

Using nanotechnology -- which manipulates tiny matter on an atomic and molecular scale - Hsieh and his team developed paints to protect the rock.

"Our analysis shows that the strength of the rock's neck could be intensified by up to three times, while the surface resistance to erosion could be enhanced markedly," Hsieh said.

So far the paint has been applied to surrounding rocks, rather than to the Queen's Head itself, but initial tests in August were unsuccessful as the paint peeled off.

Since then the ingredients have been tweaked and applied to other rocks in the geopark, Hsieh said.

- Natural progression? -

But while scientists wrack their brains for a solution, others feel nature should be left to take its course.

"As the coastal landscape was made by erosion, the lifespan of the 'Queen's Head' is limited," said Pan Han-sheng, an activist from the pro-environment Tree Party.

"I don't understand why we would want to freeze its lifespan."

The geopark conducted a survey of 1,200 people randomly picked across the island before going ahead with the paint tests.

Only 63 percent backed the scientific experiments and the survey sparked alternative less invasive suggestions, including encasing the formation in a glass cabinet.

"I would prefer a glass cabinet so that the rock can be sheltered from erosion," said Kin Kuo-yen, a tourist from China's eastern Hangzhou city.

Kin was concerned that paints might damage the rock, while a glass case would preserve it.

"It's a marvellous spectacle -- once gone, it will be gone forever," he said.

Neo-Space International has used 3-D technology to record the measurements of the rock twice each year so that it can be reproduced.

One replica already stands at the entrance to the park and has become a tourist attraction in itself.

Park administrator Kuo Chen-ling played down fears over the rock breaking down.

"Even in the worst scenario, a toppled 'Queen's Head' could be placed in a museum and attract tourists," he said, adding that there were other rocks in the park which drew visitors, including some in the shape of an elephant, a shoe and a peanut.

But with tourists to the geopark bringing in an estimated Tw$700 million ($21.54 million) of business each year to the 2,000 residents of Yehliu, some say losing the natural icon would be both an emotional and financial blow.

"It has been there since I was a kid," says 73-year-old Liu Pi-lan.

"Lots of people in Yehliu depend on tourism for their livelihoods. I'm afraid tourists would show less interest if the 'Queen's Head' fell down," he added.

"I would be heartbroken if it breaks off, we cannot do without it."