After the 1991 fall of dictator Mengistu Haile Mariam made Ethiopia more amenable to visitors, hardy tourists started to make their way to the remote town of Lalibela, perched in Ethiopia’s Lasta mountains at 2,600m. The town is home to 11 medieval rock-cut churches so revered, Unesco included them on the original World Heritage list in 1978 – a list of then only 12 sites, which now has grown to 981. Yet as more travellers have followed, some are starting to worry that increased commercialisation is eroding the area’s unique atmosphere.

According to local history, Lalibela’s churches were the grand project of early 13th-century King Lalibela, although archaeologists believe that some of the churches, including the imposing Bet Gebriel-Rafael and the nearby Bet Mercurios, were built five centuries earlier, under the rule of the Axumite Empire.

Arguably the most spectacular of Lalibela’s churches is Bet Giyorgis (St George). The church lies in a hole some 15m deep, putting its cruciform roof roughly at ground level. Giyorgis has no bricks, no blocks, no evidence of joins. Instead, the church is carved out of a single solid piece of pink rock. The 13th-century labourers who built it dug down into an outcrop, carving a trench around a single massive block, and then hewed the church from that monolith.

Visiting the church may be a priceless experience, especially in mid-January during Timkat (Epiphany), when thousands of Ethiopian white-clad worshippers, as well as tourists, descend on the churches. But tourists have been grumbling since the fee to see the churches tripled in 2013 from 350 birr to 950 birr, a ticket that covers all 11 churches and is good for four days.

“It was a shocker,” said Priscilla Champaneri, who was visiting from New Zealand. “I was thinking it would be $20 (385 birr) maximum. We were backpacking and had accounted carefully for the whole trip. We had paid so much to go there. Our hotel manager said we are not the first to be shocked.” Across the world, many religious buildings accept tourists for a price.

London’s St Paul’s Cathedral charges £16, the equivalent of 505 birr; Italy’s Sistine Chapel and Vatican Museums, 16 euros (415 birr). And Lalibela’s 950-birr, four-day tickets are on par with the 160-Cambodian Riel (770 birr), three-day ticket to see Cambodia’s Angkor temple complex or the 750-rupee (230 birr), one-day ticket for India’s Taj Mahal.

But globally, there are other religious institutions that don’t charge. Neither Paris’s Notre Dame Cathedral or Istanbul’s Blue Mosque ask for an admission fee. More importantly, some question where the money to the Lalibela churches goes, particularly as it does not seem to be used for preservation. The enormous – and many say jarringly modern-looking – shelters completed in 2008 that cover most of the churches, protecting them from rainwater erosion, were paid for by the European Union and co-ordinated by Unesco.

Instead, ticket revenue is primarily used to pay the 816 church officials – mostly priests, deacons and chanters – who work around the 11 churches, said Deacon Alemu Tseganew, who runs the Ethiopian Church’s ticket office in Lalibela. The national hierarchy of the church takes a 20% cut, some of the money goes to security and sanitation, and, Tseganew said, some of the money funds seminaries and community work, such as constructing residences for the homeless. He estimated that Lalibela’s rock-cut churches see an average of 115 visitors a day, equating to about 40,000 people a year – and ticket revenue of 40 million Ethiopian birr.

This “touristification” of Lalibela has led some Ethiopia enthusiasts to seek out more obscure churches in the far north of the country. The Tigray region – epicentre of the 1985 famine and the heartland of the Axumite civilisation that prospered between the 1st and 10th Centuries – is home to its own extraordinary rock-hewn churches. Instead of being dug down into outcrops, these churches have been cut sideways, often into difficult-to-reach cliff faces. The Axumite monastery of Debre Damo, for example, can only be reached by climbing up a 15m leather rope.

While the churches of Lalibela are more accessible, the stark, mountainous landscape and the isolated setting of the Tigray churches can be half the appeal for trekking tourists.

Perhaps unsurprisingly, the revenue-raising potential of these northern churches is also being realised – most cost 150 birr each to enter – and increasing tourism is changing the surrounding area. At the Debre Tsion church, I encountered a group of teenagers attempting to extort money from visitors by blocking the paths off the mountain on which the church is carved.

I later learned that other travellers had run-ins with the same group. A priest, standing in his own church of Medhane Alem Adi Kasho, reverently pointed out pictures of Yaysus and Maryam (Jesus and Mary) – then rubbed his fingers together in the international signal for wanting more money.

Back in Lalibela, the influence of tourists, and tourist money, continues to grow, just as it will in Tigray. Yet even throngs of visitors and a profusion of modern hotels can’t erase the majesty of the stunning churches.