Harry and Meghan's home renovations cost $4.6 million in taxpayer funds

Harry and Meghan's home is being upgraded and has use $4.6m of taxpayer-funded costs so far. Photo / Getty Images

The Duke and Duchess of Sussex have used $NZD4.6 million in public funds so far to renovate their new home.

The royal couple - who have 7-week-old son Archie together - have paid for upgraded fixtures and fittings at Frogmore Cottage in Windsor, but the Sovereign Grant has covered the cost of replacing heating, electric, gas and water main systems, as well as replacing ceiling beams and floor joists at the property, which has been remodelled from five separate living quarters into one residence.

Prince Harry and Duchess Meghan were also permitted to use the grant to install a "certain standard" of kitchen, bathroom, flooring and fitted furniture from the grant, but anything considered a "higher spec" than that approved by the palace must be met by the couple themselves.

Sir Michael Stevens, Keeper of the Privy Purse, who is responsible for monarchy's accounts, said of Frogmore Cottage: "The property had not been the subject of work for some years and had already been earmarked for renovation in line with our responsibility to maintain the condition of the occupied royal palaces estate.

"The Sovereign Grant covered the work undertaken to turn the building into the official residence and home of the Duke and Duchess of Sussex and their new family.

"The building was returned to a single residence and outdated infrastructure was replaced to guarantee the long-term future of the property.

"Substantially all fixtures and fittings were paid for by Their Royal Highnesses."

Frogmore Cottage in Windsor was turned into a single property for Prince Harry and Meghan, from five separate homes. Photo / Getty Images

The figures were revealed as part of a new Buckingham Palace report, which disclosed the total Sovereign Grant for 2018/19 was £82.2 million - or £1.24 per person in the UK.

Most of the renovations of Frogmore Cottage - which was a gift from Harry's grandmother, Queen Elizabeth - were completed shortly before Archie was born but some works, including painting the exterior, will fall into the next financial year.

However, the cost of the final work will be reported next year only if it reaches a £350,000 threshold for individual projects.

The cost of Harry and Meghan's wedding in May 2018, and additional expenses incurred since the former "Suits" actress officially joined the royal family, were included within the accounts of the Duchy of Cornwall, Prince Charles' estate, which funds both Harry and his other son, Prince William, and their children.

Those accounts showed the bill for Harry, William and their families' activities and "capital expenditure and transfer to reserves", was £5.05 million in 2018/9, up slightly from the previous year.