Glasgow 2014 has confirmed both events have a bill just short of £21 million, much greater than the £14m budgeted for when a global events agency was recruited for the job in late 2012.
Details of the increased budget emerged in minutes of the high-level 2014 Strategic Group, which show the event's organising committee (OC) had been given the task of exploring how additional cash would be spent on the ceremonies.
Minutes of the February meeting, attended by the minister in charge, Shona Robison, chief Games civil servant Francesca Osowska and other leading figures from the OC and Glasgow City Council, show "the creative content, progress with programme management and risks, and an update on the budget" were discussed and agreed.
Although the plans for demolishing the Red Road flats in the north of the city had been hatched before the meeting, the Scottish Government said they were not discussed.
But it confirmed they were part of last week's Strategic Group meeting, attended by both First Minister Alex Salmond and city council leader Gordon Matheson.
According to the minutes of the Strategic Group meeting, Glasgow 2014 deputy chief executive Ty Speer had told those in attendance that the "run of show for the opening ceremony had been agreed, development of the detail was now under way and the content of the opening ceremony is likely to be tied down by May".
It adds: "After discussion, the meeting agreed that the OC should assess whether additional budget should be transferred to ceremonies and sport presentation.
"Ty reassured the group that plans for the closing ceremony were progressing well, and that the closing ceremony would be music-focused and have a 'party' atmosphere."
The cash is expected to come from the Glasgow 2014 contingency pot, which stands at less than £10m, with more than £30m having been spent.
The Games budget includes two back-up funds: the general contingency for use in case of cost pressures, which stood at £42.3m a year ago, and an emergency pot of £24m called the Scottish Government special reserve, only to be used in exceptional circumstances with Salmond's personal approval.
A Glasgow 2014 spokeswoman said: "The total budget for the opening and closing ceremonies is £20,850,000. The ceremonies offer a unique opportunity to showcase the host nation, the host city and the talent of the Scottish people.
"As we have developed the ceremonies, opportunities have arisen to add to the spectacle to deliver truly memorable events. To make the most of this once-in-a-lifetime opportunity, we have chosen to make some additional investments in the ceremonies."
The budget for the demolition is being met by the properties' owners, Glasgow Housing Association.
Meanwhile, the petition against incorporating the demolition as part of the opening ceremony had by last night attracted more than 7200 signatures.
Former SSP MSP Carolyn Leckie, who is behind the Red Road petition, said: "Given the strength of feeling, I would hope that they will acknowledge that maybe they've got it wrong, which would be understandable."
Patricia Ferguson, local MSP and former resident, is hoping to meet organisers to discuss plans this week.One leading demolition consultant, with experience of more than 100 blowdowns across Europe, said he was shocked and angry that the police and Health and Safety Executive had allowed the plan to go ahead.
Mark Anthony, editor of Demolition News, said bringing down the towers in front of a global television audience was truly unprecedented.