A problem in government computer records may mean some elderly residents eligible for the new old-age allowance will not receive the money next week as promised.
Meanwhile, thousands of people who received letters saying they could get the HK$2,200 handout have replied that they are no longer eligible.
People over the age of 65 who were eligible for the first phase of the Old Age Living Allowance scheme - those on record as having passed the means test for "fruit money" of HK$1,090 - were to have received a green notification letter in February, and were to start getting the new handout on April 5 that would replace the current allowance.
But Mui Sau-yin, 75, a recipient of fruit money since she was 65, got a yellow second-phase notification letter - which requires the elderly to declare their assets under the new means test.
"I don't understand why the government is sending me this letter when I have been receiving [fruit money] for so long," Mui said.
The Federation of Trade Unions said it was dealing with 15 such cases.
The Social Welfare Department said a computer glitch meant a small number of records might be missing. A spokeswoman said the current data system was adopted in 2000.
"There are different reasons why this group of elderly was not included in the first phase. They were sent the second-phase forms [on March 25], and the application procedures are very simple," she said. But the delay rattled Mui, as it is not known when the second-phase payouts will be made.
"If I get the money late, I may not be able to spend it as I am ill. What if I die?" asked Mui, who has heart disease.
Leung Fat-wing, 85, received the yellow letter while his wife, 82, got the green one although both had been fruit-money recipients. "I am a few years older than my wife. Why did she get the [green letter] while I didn't?" he asked.
FTU lawmaker Aron Kwok Wai-keung said the department knew it did not have the data before 2000. "Why didn't they earlier inform the elderly who started getting the subsidy before 2000 and arrange for them to register again?" he asked.
Fellow FTU lawmaker Alice Mak Mei-kuen said the mix-up had caused unnecessary anxiety.
Social work constituency lawmaker Peter Cheung Kwok-che said the government should explain the situation to the elderly to ease their worries.
While some eligible people have missed out on the first phase, the department spokeswoman said that out of 290,000 letters sent to those deemed eligible, about 15,300 had replied they no longer met the means test.
To be eligible, a single elderly must not have income exceeding HK$6,880 a month or assets of more than HK$193,000.