Teacher Henrikus Suroto vowed his students wouldn't be cheated out of their education when the global pandemic forced schools to be closed in Indonesia's remote Kenalan village.

So he braves windy mountain roads and sheer cliff drops to visit the poor farming community in Central Java, where online classes are out of the question due to a lack of Internet service -- a luxury few parents could afford anyway.

Not only is Suroto risking death or serious illness from COVID-19, he is violating government orders not to hold in-person classes to prevent the spread of the disease.

"No one's forcing me to do this -- it's something inside telling me to do it," the 57-year-old told AFP.

"I feel a bit guilty about breaking (orders) to hold online classes, but the reality is that it isn't easy here.

"The only solution is to be close to students with door-to-door teaching," he added.

Suroto is one of a small number of teachers taking on dangerous terrain, bad weather and the chance of contracting the novel coronavirus, to reach home-bound students across the world's fourth-most populous nation, home to a quarter of billion people.

Nearly 70 million children and young people have been affected by school shutdowns which started in mid-March.

While the pandemic has sparked a boom in online learning, especially in wealthy nations, about one-third of Indonesia's nearly 270 million people don't have access to the Internet or even, in some cases, electricity.

- 'Feet on the street' -

Suroto and other Indonesian teachers say they wear face masks, but the threats of becoming sick or infecting students are ever-present.

Avan Fathurrahman, an elementary school instructor on East Java's Madura island, visits up to 11 students a day, an experience he wrote about in now-viral Facebook posts.

He admits to being scared of getting ill.

"But my fears were overcome by the call to teach," Fathurrahman said.

"I would not be comfortable staying at home knowing that my students couldn't study properly."

Aside from government calls for online learning, educational programmes are being aired on a state-owned TV channel.

Education minister Nadiem Makarim -- a co-founder of local ride-hailing app GoJek -- has acknowledged the challenges in remote learning, however, and even expressed shock at how many rural Indonesians lacked Internet service.

"We have to rely on the feet on the street -- the actual teachers that mobilise themselves to teach door to door," he said last month.

The pandemic has underscored huge challenges in updating creaky infrastructure across the nearly 5,000 kilometre (3,100 mile) Southeast Asian archipelago -- a key priority for president Joko Widodo.

"Infrastructure-wise, Indonesia is not fully ready for online learning," said Christina Kristiyani, an education expert at Sanata Dharma University. 

"Even if it was possible to do real-time video conferencing, it costs too much in rural areas," she added.

- 'Can't help them' -

Meanwhile, many rural parents struggle to fill the gap as they juggle often low-paid jobs and child care.

"I can only remind (the kids) to study because I can't help them like a teacher can," said Orlin Giri, a mother from East Nusa Tenggara, one of Indonesia's poorest regions.

"And we don't have enough money for an Internet plan," she added.

That is a common story nationwide, said Fina, a teacher on Borneo island.

"Many parents only graduated from elementary school or junior high school -- or they didn't even go to school," she said.

"Just being able to send their children to school is an extraordinary achievement."

Fina, who like many Indonesians goes by one name, opted not to visit students as she has a baby and lives in an area with a high infection rate.

"But this pandemic has taught us that, while technology is good and very helpful, it so far cannot replace the presence of teachers," she said.

- Call to teach -

As Indonesian authorities consider reopening schools, critics warn it is too early as the nation's virus curve has yet to flatten.

Officially, the country has more than 35,000 cases of COVID-19 and 2,000 deaths. But with one of the world's lowest testing rates, Indonesia's real toll is widely believed to be much higher.

And the country's paediatric association has warned that malnutrition and mosquito-borne dengue fever may be putting children at a greater risk of dying from the respiratory illness. 

Nearly 18 percent of Indonesian children under five years old suffer from nutritional deficiencies, while kids aged five to 14 make up nearly 42 percent of dengue fever patients, according to health ministry data. 

The risk was highlighted in April when an 11-year-old girl with dengue fever, which itself can be fatal, died after contracting COVID-19. 

Health authorities said the pre-existing illness could have exacerbated the effect of the virus on her weakened immune system.

Still, getting back to school can't come fast enough for some students.

"I'm bored at home. I miss the school and all my friends and teachers," said Gratia Ratna Febriani, a pupil in Kenalan village.

That feeling struck a chord with junior high school teacher Yunedi Sepdiana Sine who says she will keep answering the call to visit some 50 children a week.

"Students really miss their teachers so I feel needed," she said.

"And that's what makes me content."