Beijing will boost its housing supply by introducing a new type of affordable homes, as property prices in China's capital continue to rise at alarming rates.

By the end of the year authorities will supply 20,000 'self-use' homes--that is, meant for the owner to live in, rather than to hold as an investment--the Beijing Municipal Commission of Housing and Urban-Rural Development said on its website on Wednesday. The homes, to be available to buyers who meet certain government criteria, will be priced about 30% cheaper than comparable housing nearby.

Another 50,000 self-use units will become available next year, it said.

Home prices in Beijing have been on a tear in recent months, triggering concerns about a property bubble and rising resentment over unaffordable homes. Prices in September were up 16% from a year earlier, according to a government survey released earlier this week, after a rise of 14.9% in August.

Beijing's plan is also trying to cater to migrant workers, who haven't been able to buy low-income homes under China's restrictive housing-registration, or hukou, system, and have also been priced out of the existing private-housing market. China's leaders have recently tried to remove some of the obstacles for workers from rural areas in the cities where they live and work, part of broader economic goals to raise incomes and drive consumption.

The new self-use homes will be available to migrant families that have lived in the capital for at least five years, and have paid social-security taxes during this time.

Singles aged 25 and older who fit other government criteria will also be allowed to buy one of these homes, whose size will be capped at 90 square meters (around 1,000 square feet).

Buyers will be prohibited from selling the home for five years. If they sell after five years, they will owe a 30% capital-gains tax and be barred from buying such homes in future.

The commission also pledged to punish speculators who dodge restrictions on multiple home purchases--a cornerstone of the nearly four-year campaign to keep prices from overheating--and to intensify scrutiny of developers and their credit conditions, focusing on high-price projects and those providing 'excessive' profit margins.

Nationwide, prices in 69 of the 70 cities included in the survey were up in September from a year earlier. The average increase for the 70 cities was 8.2%, picking up from August's 7.5%.

It wasn't clear whether the 70,000 self-use homes promised by the end of next year would be ready for occupancy in that period, or still be under construction but available for sale. When completed, though, the 70,000 will 'ease the imbalance between demand and supply, adjust people's expectations and stabilize home prices,' the Beijing commission's statement said.

Jinsong Du, a Credit Suisse analyst, said new homes would probably require about two years for construction [Visa]. But he added that the impact of 70,000 homes would be significant, given that the number of new private housing units sold in Beijing last year was 122,646.

'The key question is whether the Beijing government will execute this policy exactly by the book, and allocate the new supply to qualified people fairly, or forget or change it in the future--like many previous housing policies,' said Mr. Du in a note [company registration].

In the past, fraud has been a major problem in low-cost government housing projects. Many people with incomes too high to be eligible have managed to buy by falsely claiming lower income, China's state auditor said in a report in August. Shoddy construction has been another problem, leading to widespread complaints from occupants, state media have reported.