Plans for a new luxury cruise liner on the Ganges river in the holy Hindu city of Varanasi have run into trouble, with priests worried that alcohol and meat will be served to foreign tourists onboard, contravening Hindu custom.

Nordic Cruiseline is due to start the sunrise and sunset trips later this month that will take visitors along all 84 sets of steps – known as ghats – that lead down to the water.

According to Hindu legend, Lord Shiva unleashed the Ganges from the knot of his hair and millions of Indian pilgrims travel long distances to immerse themselves in the water at Varanasi each year.

The cruises will include the cremation ghats where bodies are burned as part of Hindu funeral tradition.

Nordi Cruiseline is due to start sunrise and sunset tours along the Ganges’ ghats in September. Photograph: supplied

Manoj Poddar, a director of Nordic Cruiseline, said he had been inspired by prime minister Narendra Modi’s ambitions for the city, which is also his constituency, to start the cruise.

“If the PM is so keen to work for the welfare of the city, I thought I could add my bit by providing a new experience for tourists,” Poddar said.

The prime minister, Narendra Modi, prays at one of the ghats in Varanasi. Photograph: Kevin Frayer/Getty Images

But some Hindu priests in Varanasi, have objected to the luxury cruises: “We cannot have mutton or other meat served on the liner because the Ganga [Ganges] is sacred to us. Nor can any alcohol be served. It will be sacrilege,” said Swami Jitendranand Saraswati, general secretary of the Ganga Mahasabha, an Indian organisation working for the conservation of the river.

Many venues in the heart of the city’s old quarter refrain from serving meat and alcohol because of the city’s special status, but small shops selling alcohol can be found discreetly tucked away and some hotels serve meat dishes.

Poddar has clarified that guests will be served only strictly vegetarian meals and there will be no alcohol onboard. “Of course we won’t do any such thing. We Hindus regard the Ganga as our mother. It is the ultimate symbol of our spirituality,” he said.

But some priests were not reassured: “We won’t know what is being served onboard do we? They can do what they like and I’m sure foreigners will demand beer and wine in the evening. We want a reassurance from the government on this,” said priest Satnam Mishra.

Swami Saraswati said leftover food could be thrown overboard, “polluting” the river. The Ganges river is among the most polluted in the world, full of untreated human waste and industrial sludge and the occasional, partially-burnt corpse bobbing around in the grey water.

Since former prime minister Rajiv Gandhi launched the first project to clean the Ganges in 1986, various governments have tried to improve the health of the river. All have failed. Cleaning the river was also one of the main promises made by Modi during the 2014 general election, but the government’s $3bn plan is well behind schedule.

Local boatmen are also angry about the cruise. Sanjay Sahani, who has followed his father’s footsteps in offering boat rides, fears that tourists will prefer the luxury and fixed rates of the cruise liner to the haggling they have to do with boatmen.

“I have no other skill but rowing. If people don’t take my boat because of this ship. I will be finished,” he said.