The government has doubled the budget for the London 2012 Olympic and Paralympic ceremonies to more than £80m after David Cameron saw the plans.
The prime minister gave the go-ahead for an increase of £41m above the £40m already budgeted for the opening and closing nights' shows.
The extra money comes from within the £9.3bn Olympic public funding package.
The venue security allocation has also risen by £271m to £553m after the number of security guards was revised.
The Department for Culture, Media and Sport said it now estimated 23,700 security staff would be required at Olympic and Paralympic venues next summer, more than double the original estimate of 10,000.
The BBC's Sports News Correspondent James Pearce said funding for ceremonies would normally come from the private budget of London 2012 organisers Locog, rather than the public purse.
He said: "The money which comes in to Locog comes not from government, it comes from ticket sales, from sponsorship and marketing, and from the IOC. The government money is meant to be spent on infrastructure, on building the venues and making sure they are secure.
"The opening and closing ceremonies of the Olympics and Paralympics are some of the most important ways that Locog spends its privately-raised money but now the government has stepped in by doubling the amount of money required."
Minister for Sport and the Olympics Hugh Robertson told the BBC the money was an investment to "drive the maximum benefit for the economy and for tourism".
"That's why we've invested that £41m - it's about the impression that people take away of this country. And we hope it's an impression that people will say 'we want to come back here, do business and spend tourism money'."
The figures were announced as part of the DCMS's latest Olympic Quarterly Economic Report , in which it said the extra money had been re-allocated from savings made from the public expenditure budget for the Games.
Funding for the venue security budget is likely to rise from £282m to £553m but the government said the increase in numbers of security guards was "not in response to any specific security threat".
Following a review of security arrangements in 2010 it said it was confident the core safety and security programme could be delivered within the £475m announced in the December 2010 Spending Review.
However, it said further funding was being made available to support Olympic organisers, Locog, in delivering security at all 2012 venues by funding extra security staff as well as specialist search and screening equipment.
Mr Robertson said: "The government and Locog have now undertaken detailed analysis of the numbers of security staff required to protect the more than 100 Olympic venues.
"As a result, to ensure a safe and secure Games, they have revised the numbers of trained staff required. We are therefore investing additional funds in providing nearly 24,000 venue security personnel plus specialist security equipment."
He also said the opening and closing ceremonies were a "once-in-a-generation opportunity to showcase the very best of our country to four billion people around the world and have a potential advertising value of £2-5 billion".
"To get the ceremonies absolutely right, and boost the Games business and tourism legacy, we are putting additional investment into our ceremonies," he said.
Film and stage director Danny Boyle is the artistic director behind the Olympic opening ceremony, while choreographer Kim Gavin will lead the closing ceremony. The Paralympic ceremonies will be created by Jenny Sealey and Bradley Hemmings.
As part of the re-allocation of funds, an extra £25m has also Olympic ceremonies budget doubled been set aside for campaigns, both in the UK and abroad, to maximise the economic benefits of the Games.
According to the report the final cost of the Olympic Delivery Authority's (ODA) construction, infrastructure and transport programme is £6.865m, down £394m since July. Including funding for transformation work, this rises to £7.189 billion, which is down £61m.
'Fury' over plans
The Olympics is set to be one of the UK's biggest security tests - a 64-day operation, from when the Olympic village opens on 13 July to the time the Paralympic village closes on 12 September, covering 34 venues across Britain.
Last month Defence Secretary Philip Hammond said ground-to-air missiles would be deployed to protect the 2012 Olympics if deemed operationally necessary, after reports emerged the US was unhappy with the UK's security plans.
The Guardian had claimed the US was furious with security plans and wanted to send up to 1,000 of its own people, including 500 FBI agents, although the US Embassy's Charge d'Affaires later rejected the story and said she had "the utmost confidence in the British government's arrangements to ensure safety and security for the Games".
Security personnel - which will be drawn from private firm G4S, the military and Locog volunteers - will be operational at more than 100 competition and non-competition venues across the UK.