Downing Street has said it would "pretty extraordinary" if Margaret Thatcher was not given the expensive and large ceremonial funeral at St Paul's Cathedral as planned.
The cost of Wednesday's procession from Westminster to St Paul's and the funeral itself has been estimated to be as much as £10m.
The government will only publish the full cost to the taxpayer of the event after Wednesday's lavish event and has not given a formal estimate of how much it will be.
On Monday the prime minister's spokesperson refused to say whether there was any budget or limit to the expense.
"The government has not given an estimate. What the government will do after the funeral is publish the cost to the public purse," the spokesperson said.
And he said people around the world would think it odd if the UK chose not to honour one of its former prime minister's in the way planned.
"When it comes to costs, it would be considered pretty extraordinary by many people here in the UK and abroad if we did not mark her passing in the manner that we are doing," he said.
A ComRes survey over the weekend found that only 25% of people think the funeral should be funded form the public purse and that 60% are against the idea.
Cabinet Office minister Francis Maude told Sky News on Sunday that the ceremony, which will include 700 members of the Armed Forces, was not "not over the top in any way".
The list of dignitaries expected to attend the funeral include former prime minister's Tony Blair and Gordon Brown as well as representatives from foreign governments.
The United States has yet to confirm who will represent the Obama administration, however all former living US presidents as well as former secretary of state Hillary Clinton have been invited.
Downing Street said David Cameron could be expected to engage in some bilateral meetings with the representatives of foreign governments who will travel to London for the funeral.
Left-winger George Galloway will attempt to frustrate plans to cancel Wednesday's prime minister's questions so MPs can attend the funeral of Baroness Thatcher.
The Respect MP has said he will try tonight to block a government motion dropping Commons questions and delaying the start of business to 2.30pm, after the funeral has taken place.
Ministers had hoped the motion, tabled by Leader of the House Andrew Lansley, would go through "on the nod" at the end of Commons business.
However Galloway has said he will take advantage of Commons rules which mean that if one MP shouts "Object", the motion will either have to be withdrawn, allowing PMQs to go ahead as normal, or the Government will have set aside parliamentary time tomorrow so that it can be debated and voted on.
"It really is imperative that the Prime Minister is questioned, among other things, about his decision to impose a quite unnecessary and expensive early return of Parliament which was simply a hideous outpouring of right-wing eulogies and rants doused in crocodile tears," he wrote on his website.
A full military rehearsal for Thatcher's funeral has took place in the early hours of this morning.
More than 700 serving Armed Forces personnel gathered in central London before dawn as a Union flag-draped coffin was carried on a horse-drawn gun carriage from St Clement Danes, the church of the Royal Air Force, down the Strand to St Paul's Cathedral.