Sau Wah House at Sau Mau Ping Estate was cordoned off on Friday afternoon, after sewage samples there were found to contain the virus.
The lockdown finished at around 1 pm on Saturday, and residents with negative test results were able to leave the building.
In all, about 2,070 people were tested, with 259 of them gave preliminary positive results.
There were also 36 cases deemed indeterminate.
Another block in the same estate – Sau Yee House – turned up 273 preliminary positive cases and 40 indeterminate cases.
The block was sealed off at 7 pm last night.
Meanwhile, health authorities have discovered another 85 preliminary positive cases following the lockdown of a block in Tseung Kwan O.
More than 900 people in Block Five of On Ning Garden were tested overnight.
There were also seven indeterminate cases.