Water was gushing on to St Vincent Street and spilling out on to nearby streets.
And water bosses said businesses may face further disruption while repair work is carried out.
People walking near the leaking Scottish Water Works – which extend from the junction of Renfield Street/St Vincent Street to West Nile Street – were forced to jump through the massive puddles or cross the road to avoid getting soaked.
Mark Williams, 28, an administration worker who lives in the South Side, had travelled by train into Central Station.
As he walked to his office, he said: "I couldn't believe it when I walked up Renfield Street this morning.
"I noticed the water yesterday, but today it is like a swimming pool. I'm surprised I have seen no workmen trying to sort it.
"I am going to have to walk into the middle of the road so I can get across to St Vincent Street."
Businesses said the leak had been constant since Friday and want to know why no repairs have been done.
Craig Thomson, manager of clothing shop Fat Buddha Store in West Nile Street, said: "I noticed it on Friday and called Scottish Water. I was told someone would come out.
"But no-one is working to fix it and it is getting worse."
The works are part of a major upgrade to the network of pipes in the city centre, which is resulting in temporary disruption and closures.
A Scottish Water spokesman said: "We have been attempting to repair a burst on this section of pipe for the last three nights. The repair on a faulty valve has proven very difficult because the main is under pressure.
"We had a meeting with the roads department this morning to agree that we will work overnight tonight to get the burst repaired. We are working out what traffic management measures, if any, will be in place.
"We will need to switch off the supply going through this large water main and this may result in loss of supply to some properties in the Trongate area.
"We are looking at how to minimise inconvenience to residents, businesses and commuters and provide alternative supplies where possible."
