Buildings Department officers will this week begin handing out as many as 200,000 warnings and demolition orders to the owners of village houses with illegal structures.
It marks the start of a crackdown on unauthorised additions to homes that could take as long as 10 years.
Most villagers appear to have spurned the government's offer to register illegal structures in return for a temporary reprieve from enforcement measures.
By the middle of this month just 11,000 had signed up to a scheme under which they can keep their homes unchanged, subject to five-yearly checks.
It's not known how many village homes have illegal additions.
The Heung Yee Kuk, the lobby group for indigenous New Territories villagers, estimates that 35,000 homes have unauthorised structures.
But rising rural leader Junius Ho Kwan-yiu believes the figure could be as high as 200,000.
A specially formed "village house section" in the Buildings Department, with a director, 40 staff and an annual budget of HK$36 million will tackle the illegal works.
The department has made it clear enforcement action will be taken once the deadline for registration passes on Tuesday. In most cases, warning notices telling owners to demolish illegal structures will be handed out first. If the owners fail to comply, demolition orders will be issued.
Democratic Party legislator James To Kun-sun said the tremendous manpower and public money involved underscored the fact that the growing number of illegal structures in the New Territories had become a major social issue. To said there were questions the public needed to discuss. "Does our society want to spend hundreds of millions of dollars on clearing the structures or on health care services by adding a few more beds in hospital?" he asked. "The enforcement takes time, but it isn't insoluble."
Choy Kin-kuen, president of the Hong Kong Institute of Engineers and a retired senior Buildings Department official, said the enforcement action must go ahead. "It is unhealthy to see those structures surrounding our living space," he said. "They should be cleared, especially when urbanites are questioning if preferential treatment is given to villagers. The dilemma is that it involves a huge cost."
The Buildings Department declined to say whether it would outsource the job of identifying and inspecting illegal structures, as has happened in the past.
Since 2001, the government has undertaken to clear 800,000 unauthorised structures identified as dangerous in urban areas, but it has so far cleared only half of them.
As the spotlight fell on illegal structures beyond urban areas, rural leaders put up a fight to try to stop a similar crackdown, even calling for a blanket amnesty in New Territories villages.
The issue has led to an urban-rural divide and has even split the rural authority itself.
While the kuk's leader, Lau Wong-fat, urged villagers to report their structures, Ho, chairman of its Tuen Mun rural committee, advised the opposite.
Ho, a lawyer, said the register would become a record of villagers' violation of building rules.
Sources close to the three professional institutes - for architects, surveyors and engineers - say they are unlikely to back Ho's proposal to legalise some of the structures.