Diversions were in place around Nelson Mandela Place and Renfrew Street as work was carried out at both busy locations.
There were traffic hold-ups as buses, cars, vans and cyclists tried to negotiate the diversions and motorists were forced to weave around traffic cones on stripped-back road surfaces.
As reported in last night's Evening Times, Scottish Water is carrying out roadworks in Nelson Mandela Place as part of its £3.5 million upgrade to replace five miles of crumbling mains in the city centre.
The programme, which began last July, has already caused a series of disruptions for motorists, but the water authority says the work will improve services to thousands of customers.
Meanwhile, Renfrew Street is down to two lanes between Cambridge Street and Renfield Street until Thursday due to resurfacing work.
A second section of Renfrew Street, between Renfield Street and West Nile Street, is reduced to one lane in each direction.
Daryl Harper, 21, from the South Side, who works for a letting agent, said customers are complaining that the roadworks are making them late for viewing properties.
However, onlookers said they were pleased to see the work being carried out.
James Watson, 26, who works in the city centre, added: "It is about time they sorted the potholes out."
Scottish Water said it liaised with the council roads department before the work began.
Nelson Mandela Place is closed from its junction with West Nile Street to the junction with West George Street and Queen Street, and diversions are in place to George Square.