Homeless vagrants are seeking unholy vengeance on a humble East Village pastor and his family who are trying to boot their fetid encampment from their church’s doorstep.

“It’s gotten so bad that we might move away. I’m fearful for my childrens’ safety,” a worried Irina Belets said of the bums’ war against her and her husband, Ivan, leader of the First Ukrainian Assembly of God flock.

Alarmed by a growing daily gathering of junkies and hobos, the Belets took matters into their own hands July 22 by sprinkling Comet bleach powder all over the sidewalk in front of the church, at Third Avenue and East Seventh Street in Cooper Square.

The cleanser fended off the unwelcome interlopers for just a day. “They retaliated and spray-painted all kinds of profanity like ‘f–k you’ on the walls,” Irina said. “They also dumped garbage all over the powder and left a garbage bag filled with used toilet paper.”

The Belets, parents of two toddlers, have long suffered the annual spring and summer horde of homeless who take advantage of warm weather to move from shelters to camp in city streets.

But this year, the couple says, the homeless swarm is worse than ever.

“Since [Bill] de Blasio became mayor, it’s become considerably worse,” Irina, 30, told The Post. “Police let them set up camp and do nothing about it. Every morning when I left for work at 6 a.m., there were at least five homeless people sleeping outside. The most I ever saw was a few weeks ago: There were 11 people and four dogs.”

The Belets often see vagrants using heroin outside the church and across the street at Cooper Triangle Park.

“I saw them shooting up all the time when I took my kids to day care,” said Ivan, 36. “It’s just not right.”

Ivan tried to reason with the encroachers, who are mostly in their 20s and 30s, but “they wouldn’t listen,” he said.

“They’d say ‘we don’t want to conform to society’ when we asked them to use a bathroom or find a healthier living situation,” said Irina.

The Belets say they have complained to the city constantly to no avail. They say they have filed at least five complaints through the 311 hotline, and the NYPD confirmed it has received at least 14 calls to 911 this year for the church address, including five reports of disorderly persons.

The nightmarish conditions have reached an all-time low this year partly because of a sidewalk shed in front of the building next to the church.

The 4-foot-wide shed extends 10 feet in front of the church, stopping just short of its front door. City records say the shed, installed in November, may remain in front of the next-door apartment building, 65 Cooper Square, until February 2018.

The shed gives the bums plenty of space to sprawl out.

“They like it because it protects them from the elements,” said Irina, who works as an engineer.

The vagrants urinated on the church steps — forcing the Belets to scrub them every day for months in a futile effort to get rid of the “unbearable” stench, Irina said.

Some members of their flock began to skip their weekly Sunday service because of the putrid smells.

“People were always asking us, ‘What are you doing about this?’ ” Irina said of the odor. “They were disgusted by it.”

In mid-July, Irina “nearly stepped in a pile of human feces” outside the church. Revolted by the filth, the couple decided to spread heaps of cleansing power on the sidewalk outside the 80-year-old house of worship.

Last week, the walls of the gray four-story cement church remained peppered with tags — one reading “f–k the police” — and a small plastic baggie, possibly to store drugs, was on the sidewalk.

Despite the retaliation, the powdered bleach appears to be keeping the bums at bay for now.

But Irina Belets suspects it’s only temporary.

“I think they’ll return and things will go back to how it was,” she said. “We need real help. We need the city to do something.”