The Coalition Government has been accused of wasting millions of pounds after appointing banks to deal with the planned privatisation of the Royal Mail.

UBS, Goldman Sachs, Barclays and Bank of America Merrill Lynch will work with the Conservative-Liberal Democrat administration, the Royal Mail and advisers to prepare for the controversial sale.

Opponents said the banks were set to make £30 million.

Business Minister Michael Fallon said no final decision had been made on the sale's structure.

He said: "Preparations for the sale of shares in Royal Mail continue to build momentum and these appointments represent another important step towards a sale of shares this financial year.

"While all options for the form of sale remain open, it is important that we are in a position to move ahead swiftly with our chosen route once we take the final decision.

"Given the lead time and preparatory work involved in readying an IPO [initial public offering], the appointed banking syndicate will work to make sure we are ready to proceed when the time comes and will be able to deliver strong, high-quality investor demand to ensure a successful IPO."

The appointments of banks to junior syndicate positions for an IPO will be announced in the coming months.

The Communication Workers Union has warned postal services will be hit by privatisation.

General Secretary Billy Hayes said: "The Government is wasting significant sums of taxpayers' money on a deeply unpopular and unnecessary privatisation agenda.

"Throwing public money at banks to flog a national asset is poor use of public funds. This Government has got it wrong."

Mario Dunn, of campaign group Save Our Royal Mail, said: "Banks are set to make up to £30 million when the Government sell off Royal Mail. Once again consumers will lose out when prices rise and deliveries are reduced, but banks make millions."

He said the public strongly oppose the selling off of the cherished British institution, and knowing that Goldman Sachs is set to make huge profits added insult to injury.

A Department for Business spokesman said the figure quoted by the Save Our Royal Mail campaign was pure speculation. "They do not know the basis on which the banks we have appointed today will be paid, and they will only be paid if the Government proceeds with an IPO," he said.

"As with any other IPO, the banks will get a percentage of the institutional investment they attract. We have agreed fees that are extremely competitive."