Nepal's government has been accused of "inaction and apathy" after it emerged that 10 out of 250 endangered elephants are suffering from tuberculosis (TB).
Officials at Chitwan National Park say government ministries have ignored requests for help to give treatment.
They warn there is a danger that TB may spread to humans and other animals.
The park in southern Nepal attracts thousands of tourists every year. The government says that the detection of TB in elephants is a new development.
"It is uncommon," Babu Ram Yadav of the Department of National Parks and Wildlife told the BBC's Sushil Sharma in Kathmandu.
He said that the TB outbreak needed to be taken seriously as the disease could spread to humans and new-born elephants.
But Mr Yadav ruled out government negligence in the upkeep of the elephants as a cause of the disease.
"They have been well taken care of, with three persons assigned to look after one elephant," he said.
Staff at the park say tests have confirmed that at least 10 out of 100 domesticated Asian elephants in Chitwan had contracted the disease in the past two years.
"As medication for each infected elephant costs no less than 50,000 rupees [more than $1,200], curing them at the local level is not possible," national park official Rameshwor Chaudhary told Kantipur.com.
"They need continuous medication for 18 months. This is not possible without help from the departments of National Parks and Wildlife Conservation and the Ministry of Forests."
Park staff say it is the first time that TB in elephants has been reported in Nepal.
"This is serious because it may spread to human beings," senior veterinary official Kamal Gaire told Reuters news agency.
Officials say that the infected elephants have now been quarantined.
It is not clear what strain of TB they have, or whether their condition is treatable.
Nepal has about 150 elephants in the wild and about 100 which are domesticated and used for safaris by private hotels and state-run national parks.
Elephants are a protected in Nepal and killing them carries a jail term of up to 15 years.