A 90-year-old lighthouse perched on a lush cape in northern Spain is at the centre of a cultural row after a dazzling paint job by a local artist left the tower outshining its lamp – and some critics blanching.

For almost a century, the lighthouse, near the Cantabrian town of Ajo, was a mute, monochrome sentry beaming its light out over the Atlantic.

Now, thanks to a commission from the local council and the port authority, the 16-metre tower is a collision of colours, geometric shapes and animals, which is intended to boost visitor numbers to one of the lesser known spots on the coast of Spain.

According to the regional government, some of the money raised through marketing or events at the site will go to funding food banks in the area.

The recently completed project, called Infinite Cantabria, is the work of the artist Okuda San Miguel, who was born in the region’s capital, Santander, and who often draws on his roots for inspiration.

“This time, I’ve used animals from Cantabria – wolves, bears, seagulls and vultures,” he said.

“The colours and geometry represent indigenous culture and multiculturalism and freedom. I also really wanted to show the wonderful importance of nature in a place like Cantabria, where there are still wild beaches and where you have greenery that stretches almost all the way to the sea.”

Not everyone, however, shares his enthusiasm or his vibrant palette. Earlier this year, almost 4,000 people signed a petition calling for the building to remain white and arguing the makeover “completely changes the styling of the Cape Ajo lighthouse and does not respect Cantabria’s architectural heritage”.

Five cultural groups also wrote to the local mayor, asking him to reflect on whether the project was “appropriate” and whether the lighthouse was the best candidate for such treatment.

This week, members of the regional branch of the Izquierda Unida (United Left) party went a little further by reporting the matter to prosecutors and asking them to examine whether the council and the port authority had infringed any heritage laws or misused their powers. An investigation has been opened.

Okuda, who was speaking as he travelled to Germany to paint a seven-storey building for a film festival, said he was surprised by the reaction from some in his home region.

“Of course I understand the criticisms – and that some people want to keep things the way they’ve always been, but I think my work, among other things, is about bringing my language and iconography to places to give them new life,” he said.

While the artist pointed out that he had no control over people’s response to his work, he said: “At least it hasn’t left anyone feeling indifferent.”

Thousands of people have visited the lighthouse since its new colour scheme was unveiled on 28 August. Okuda said schoolchildren had been sharing their own drawings of his work.

“One little girl even showed me the pictures she’d done of the lighthouse,” he said. “That was just wonderful. For a while now, children in schools in Spain, in Miami and elsewhere, have written to me to tell me about how my work has helped them learn about art and about colours. That makes me really proud.”

The artist, whose other projects include transforming an abandoned church into a multicoloured skate park, is waiting to see how long his efforts in Ajo will endure.

“The port authority has said it’s going to be a non-permanent work that will last for eight years, so we’ll see what happens it eight years’ time,” he said. “But I hope it stays this way for ever. We’ll see.

“At the end of the day, the most important thing about a lighthouse is its lamp, and that’s still working, even if all boats today have GPS and modern systems that have almost done away with the need for lighthouses.”