The shouting in the sixth-storey flat started at about 8pm on Wednesday and it did not let up for the next four hours.
Some neighbours who heard the heated exchange between male and female voices said they were surprised, as it was the first time such an incident had occurred in the unit at Block 606, Clementi West Street 1.
But others said they had heard quarrelling in the flat since Monday.
At times, the yelling was so loud that people at a coffee shop at the foot of the next block could hear the voices. But none of them could make out what the fight was about.
There were also sounds of doors being slammed and glass shattering.
At about 11.30pm, a neighbour, Mr Bah Soo Liang, 50, who was at the coffee shop, could not take it any more.
The renovation designer said he knew the couple who have lived there with their grown-up son and daughter for more than 10 years. Mr Bah told The New Paper in Mandarin yesterday: "I shouted at them, 'Have you had enough?'"
His intervention brought the daughter to a window, where she waved at Mr Bah and shouted for help.
"She said, 'Uncle, call the police,'" said Mr Bah.
"So I asked my wife to call the police."