Ever since a monster blast ravaged the arches and high ceiling of his family home in Lebanon's capital, Bassam Bassila says a real estate developer has been hounding him to sell.

"The owner of a tower block nearby is trying to pressure me into selling him my home so he can raze it to the ground" and "build a tall tower" instead, the 68-year-old said in Beirut's Monot neighbourhood.

A massive explosion at the Beirut port on August 4 that many blame on official negligence killed more than 180 people, wounded thousands and laid waste to some of the capital's most picturesque streets.

With survivors still picking through the rubble, property sharks are moving in to take advantage of distraught homeowners, sparking outrage over yet another disaster in the making, this time targeting the country's heritage.

Standing inside his living room turned balcony after the wall separating them was blown off, Bassila said the developer had first approached him some time before the blast, offering to buy his apartment after acquiring the ground floor of the same building.

"Eventually you will leave," the developer threatened at the time.

And now he is back, ramping up pressure on Bassila to sell the home he inherited from his grandparents by refusing to prop up the ceiling of the flat below -- meaning Bassila's apartment could collapse.

A former photographer now eking out a living as a taxi driver, Bassila says he cannot afford to restore his family home without financial aid. But he is also determined not to give it up.

"I was born in this house and my father was before me... I can't live anywhere else."

- 'Real estate vultures' -
Of 576 heritage buildings surveyed in the wake of the explosion, including 331 in the port's immediate vicinity, the culture ministry says 86 were severely damaged. 

Of those, 44 risk complete collapse, while a further 41 could partially fall down.

In the days after the explosion, Bishara Ghulam, the mayor of the Rmeil district near the port, said he received an unexpected visitor among those flocking to his office to report damage to their homes.

"A man turned up who said he was a real estate broker. He said he wanted to buy houses damaged in the blast, and would pay whatever the owners wanted," Ghulam said.

"I told him we weren't selling."

The blast came as Lebanon was already suffering its worst downturn in decades, plunging a portion of the middle class into poverty, drastically weakening the local currency and trapping people's dollar savings in the bank.

Reports of developers now trying to snatch homes -- sometimes in exchange for rare dollars -- have sparked anger among activists.

In the capital, banners have appeared reading "Beirut is not for sale".

Political and religious figures have issued condemnations, with Maronite Christian Patriarch Bechara al-Rahi warning against real estate "vultures" hovering over Beirut.

The culture ministry has said damaged properties must be restored before transactions can take place, while the finance ministry banned the sale of any listed property without official permission.

- 'Our history' -
Naji Raji, the founder of the Save Beirut Heritage initiative, said: "We've heard from people who have received offers from investors linked to certain politicians."

These developers were bent on profit and coveted central Beirut real estate as it was a "prime touristic area" but would likely change its appearance with no regard for heritage, he said.

In the devastated Gemmayzeh neighbourhood, architect Rita Saade surveyed the damage sustained by the home that once belonged to her great-grandparents.

Between the mint green walls of a room held up by arched pillars, she pointed to where the floor had partially caved in. Wooden slats from broken window shutters and shattered drinking glasses lay in a pile nearby.

"This is heritage and it needs to be restored," said the 23-year-old Saade. But "we can't afford to restore it on our own".

Audrey Azoulay, the head of the UN's culture and education body UNESCO, Thursday said the agency hoped to raise "considerable" funding to help with reconstruction.

"It's Beirut's soul that's on the line," she said. "Without its historical quarters, its creators, Beirut would no longer be Beirut."

After the 1975-1990 civil war, the real estate company of slain billionaire and former premier Rafic Hariri was criticised for not preserving the city's soul after it bought up and transformed large swathes of central Beirut.

Outside his damaged home in Gemmayzeh, Alain Chaoul said he had no idea what he would do next.

"My house is worth three million dollars, and would cost $200,000 to renovate. I don't have a penny to fix it."

But it's not for sale, he said. "It's our history."