Chief Executive John Lee said giving public housing tenants a greater chance to buy Home Ownership Scheme units is a step towards helping them climb the housing ladder and should not be deemed unfair to the broader public.

In his Policy Address on Wednesday, Lee announced a revision of the allocation ratio for the subsidised flats, changing it from 4:6 to 5:5 between green form, or current public housing residents, and white form applicants.

During a TVB programme aired on Sunday, the CE was asked whether the move was intended to "pressure" the general public into pursuing private property to boost the market, given the quota for green form applicants had not been fully utilised in the past two years.

"Don't resort to conspiracy theories,” Lee said in response.

“Frankly, when you're allocating housing, flexibility is crucial.

“The ratio between green and white form applicants could be different every single time. If one side doesn't use up the quota, then it could be re-allocated. There can easily be differences, and it's the role of the government to adjust these.”

Lee also rejected suggestions the revised allocation favours well-off public housing tenants, who are being urged to move out in accordance with government policy.

"Typically we expect a duration of about 10 years for residents to make progress. Then we'll give them the opportunity to return the public housing units to those who need them. I believe this approach is reasonable,” he said.

Meanwhile, Lee said the relaxation of mortgage rules as announced in this year's Policy Address was based on the assessment that the private housing market is developing in a healthy manner.

Under the new policy, the maximum loan-to-value ratio for all homes has been adjusted to 70 percent, regardless of their value, and the maximum debt servicing ratio has been raised to 50 percent.

The CE said he has not detected speculation following the change, and stressed that the chances of speculative activity under present market conditions are very low.