It comes ahead of a busy period for the city, with road closures due to come into force ahead of the festival season at the end of July.
George Street is usually closed to traffic during August, when bars and venues are permitted to extend across the road.
Willie Hamilton, Lothian Buses chief operating officer, said the current closures posed a “significant challenge” to operators and commuters.
He said: “Princes Street is right at the heart of Edinburgh’s public transport network, so any closure has a huge impact.
“We are involved in discussions on a daily basis and I would urge anybody, when they are travelling to check in advance.
“It is a fluid situation and it will be changing, sometimes hour to hour.”
He added: “Once we’ve got a date for length of time for this, that will determine whether the upcoming closures, for example of George Street for the festival, has to be a consideration or not.”
