A pohutukawa tree in Spain has stirred up debate on whether the Spanish were the first Europeans to reach New Zealand, before the Dutch and the British.

The giant pohutukawa is a big attraction in the Spanish north-west coastal city of La Corunna, capital of the province of Galicia.

La Corunna's mayor chose the tree as the city's floral emblem, and many locals believe it to be 400 to 500 years old.

This would mean it came to Spain before Captain Cook sailed to New Zealand in 1769, and possibly even before Abel Tasman's voyage in 1642.

But Landcare Research botanist Dr Warwick Harris, who recently visited La Corunna, has another idea on how a New Zealand native got to Spain.

"I have the romantic idea that it was brought into Spain by the British during the Napoleonic Wars and can be linked to the heroic story of Sir John Moore," he said.

Moore took a small British army into Spain in 1808 to check the French invasion, but was forced to retreat, pursued by Napoleon Bonaparte and a huge army.

Moore eventually led his men more than 400km to La Corunna, where British ships were waiting, but in the last phase of the evacuation his arm was blown off by a French cannon and he died.

"At some stage the British must have recovered Moore's body, and laid him in a tomb in what is now the Garden of San Carlos, created in 1834," said Dr Harris.

"We know that Captain Cook brought back plants from his first voyage to New Zealand, and within 10 years there was commerce in those plants in England. We don't know about pohutukawa specifically, but we do know that the British were largely responsible for introducing New Zealand plants to Europe."

Dr Harris said pohutukawa thrived in the frost- and pest-free coastal regions of Galicia.