Olympic officials revealed more details about how London Bridge and Waterloo railway stations will be affected by next summer's games when they appeared before City Hall's transport committee on Tuesday morning.
"We want to encourage people to have a great time in the summer of 2012," said Hugh Sumner, director of transport at the Olympic Delivery Authority.
"Will there be areas of stress on the transport system? Yes there will.
"For example on day 3 when there is an equestrian event down in Greenwich, London Bridge will be very, very busy indeed as people try to get there in advance of the midday session when the cross-country event starts.
"We are trying to give people a very clear idea of when and where those hotspots are, so people can plan around them."
Last month we reported the advice of Transport for London commissioner Peter Hendy who told London Bridge commuters to "have a beer before you go home" because the station will be so packed with spectators returning from the equestrian events in Greenwich Park.
Deputy Mayor Isabel Dedring told the committee that Transport for London will be releasing more detailed information later this month.
Conservative assembly member Roger Evans asked which other stations would be particularly affected by large crowds during the Olympics.
"Waterloo will be challenging because a lot of people will be coming in on the south west main line and then moving on to events either in the centre of town or the east of town," said Mr Sumner.
He added: "At London Bridge the challenge will be counter-flow traffic: you've got commuters coming into town but people trying to leave to see the equestrian events in Greenwich Park."
Labour's Val Shawcross AM picked up the question of London Bridge which she described as "an extreme hotspot".
"You need more than a 30 per cent decrease in the usual demand for that to cope," she said, asking what contingency plans had been put in place.
Ben Plowden, Transport for London's director of better routes and places, added: "The phasing of who you communicate with is also important.
"For those people who will be travelling as regular Londoners next summer, if you start telling them now what London Bridge might be like on day 3 it simply won't have much resonance because it's a long way away.
"In the last six or eight months we've been talking in detail to businesses about how they need to enable their staff, visitors and contractors to change their travel behaviour during the games time."
"So for example if people are potentially working from home on the busier days of the games, does the company have adequate bandwidth for people to log on remotely to the company's IT system? Do they have the HR policies that allow them to provide flexible working from home as part of their standard practice?"
Val Shawcross asked about coordination between London Underground and national rail operators at the mainline stations.
She asked: "For example, is there an overarching Tannoy system in London Bridge? Are they practicising control and management of passenger flows in London Bridge?
"It is very busy at the moment and they don't seem to have much active management of passenger movements."
Mr Sumner replied: "The answer to your question is yes."
• Find out about transport during the Olympics at www.tfl.gov.uk/2012