Residents described the dramatic scene on the north side of the river, just west of the Kingston Bridge, as "shocking" and "terrible".
The entire quay wall collapsed, leaving a deep crack revealing bare soil, concrete and metal foundations.
As well as the section of concrete slabbed pathway, the grass verge between the path and Anderston Quay road has also fallen into the hole.
The white fencing has broken and the quay wall is cracked and bulging. As the tide came in, water flooded into the hole.
Eva Arrighi, who lives in an apartment on the south side of the river front, said she is worried about the security of her own property now.
She said: "We can see it from the house, it is terrible.
"We didn't notice that this area was cordoned off last night, but this morning we saw it.
"We were shocked because we live right on the river so we are con-cerned about whether the quay wall is safe.
"It does make you question, is it safe to walk along the river?"
Eva and her partner, Michael Bannister, 32, regularly walk with four-year-old Hector, January, 2, and Henry, 4, along the river. She added: "It is as if the earth behind it has forced the walls, it is where the Waverley used to sit."
The council fenced off the walkway last Wednesday after assessing a depression in the path. That fence now stretches from the Kingston Bridge to the Anderston Quay apartments.
A spokesman from Glasgow City Council said: "A depression in the walkway was noticed last Wednesday. That afternoon, council staff fenced off the walkway. The assess-ment indicated a failure in the quay wall.
"A local contractor with a good working knowledge of the quay walls in the area is now on-site.
"The contractor is carrying out investig-ations on the quay wall and is monitoring it daily.
"Local businesses and residents have been informed."
Strengthening work was carried out on parts of the quay wall for the construction of the Riverside Museum of Transport.