Public funding to support Prince Charles rose by 11% during the past financial year, taking the contribution from the taxpayer to almost £2.2m, it was disclosed on Friday.

The accounts, an annual glimpse into the finances of the royal household, also showed that the Prince of Wales' spending rose by 3.6% to over £20.2m. They cover the period in which the wedding between Prince William and Kate Middleton took place, the cost of which royal aides have said was shared between the families of the bride and groom.

The accounts also showed an increase of 3% in the income that the Prince of Wales receives from the Duchy of Cornwall, the estate given to the heir to the throne to provide him with a living, to £18.3m.

The increased contribution from the public purse has largely been spent on the official overseas tours undertaken by Charles, his wife Camilla, the Duke and Duchess of Cambridge and Prince Harry, according to Clarence House.

The government justified the increased cost of the foreign travel, saying that the tours were necessary to promote "foreign policy objectives and UK interests throughout the world".

Anti-monarchists, however, criticised the rising bill at a time when "the country is facing sweeping cuts to public spending". They also disputed that all the royal heir's travel was for official purposes.

Clarence House said total spending on official travel for the five royals came to £1.31m, a 22% rise on the previous year.

The government was keen to point out that the overseas visits by the royals were "of real value to the country". Simon Fraser, the head of the Diplomatic Service, said: "The visits of the Prince of Wales have supported British business, investment and development goals and promoted our values around the world."

Charles and Camilla travelled almost 48,000 miles to and from official engagements at home and abroad, according to Clarence House. They undertook 804 domestic and foreign engagements, alone or together, during the year, and hosted almost 9,500 people at events at royal residences, according to the accounts.

Aides added that the travel bill covered tours royals have been asked to undertake by the government. They said that the increased bill was due to several factors, identifying in particular more trips abroad by the five royals and the "longer distances travelled during those visits".

They singled out visits such as the Prince of Wales' trips to the US, Kuwait, Qatar and Saudi Arabia, as well as tours with the Duchess of Cornwall to Norway, Sweden and Denmark in March "in the first of their overseas tours to mark the Queen's diamond jubilee".

However, the accounts did not disclose the cost of the wedding of the Duke and Duchess of Cambridge last year. Prince Charles' spokesman, Paddy Harverson, said most of the expense was covered by the bride and groom's families, and that "it would be rather impolite to give away the cost of a wedding". The government footed the bill for some aspects of the ceremony at Westminster Abbey, such as security.

Royal aides also were also quoted as saying it would be "impolite" to give a cost for the Duchess of Cambridge's wardrobe. It falls under expenditure for official duties and charitable activities – a total of £9.8m for the year. This week, tabloids claimed that Charles pays for the cost of the clothes she wears for official engagements and that the bill was in the region of £35,000 a year.

The Prince of Wales' tax bill rose marginally from £ 4.39m to £4.49m.

The accounts disclose a slight increase in staff who work for the prince and his family. They include two valets, a butler, an equerry, a master of the household, three chauffeurs, 10 house managers and housekeepers, five chefs and kitchen porters and 19 gardeners and estate workers.

Republican campaigners called for an urgent review of royal finances and an "end to the 'something-for-nothing' culture in the royal household".

Graham Smith, chief executive of Republic, said "Year on year, Charles continues to spend more public money on travel, much of which is for personal trips. When the country is facing sweeping cuts to public spending, Charles Windsor wilfully helps himself to whatever travel funds he wants or feel he needs."