NHS bosses in Gwent allegedly spent up to £13,000 too much on bananas in one year by not seeking out the best deal.

Anuerin Bevan Health Board, which runs the Royal Gwent Hospital in Newport and Nevill Hall in Abergavenny, could have overspent by £43,524.68 in a year on just five common fruits and vegetables.

Welsh Conservatives asked health boards how much they were paying for five everyday items: apples, bananas, jacket potatoes, salad potatoes and cucumbers.

They took figures from four random months in 2013 and 2014 and calculated annual figures from these.

In December 2013, the market price for an 18kg box of bananas was £11.88, but Aneurin Bevan Health Board paid over £19 a box. With the health board ordering 141 boxes of bananas that month, it worked out at an overpayment of £1,083.22 - or around £13,000 extra annually if patients ate the same amount of bananas at the same price throughout the year.

In the same month, Aneurin Bevan paid £852.88 too much for salad potatoes.

The Wales Audit Office has been asked to look into the claims.

Contracts for 2010-14 signed by Welsh health boards stipulated that prices for fresh fruit and vegetables should be 2 per cent above market prices for the previous four week period.

But in April 2014, Aneurin Bevan paid 94 per cent above published market prices for cucumbers, along with three other health boards.

The figures show the Welsh NHS as a whole could have paid £385,614.55 too much over four years.

Other health boards came under criticism too - neighbouring Cardiff & Vale UHB could have overspent £17,055.60 in a year.

Tory shadow health minister Darren Millar AM said: “These figures show how the Welsh NHS has been paying hundreds of thousands of pounds above market rates for everyday fruit and vegetables, meaning less money to spend on patients and hardworking staff.

“These figures show the Welsh NHS could be overcharged by as much as £385,614.55 for just five basic items, so this could be just the tip of an enormous iceberg.

“These figures raise serious questions about the measures in place to monitor what hospitals pay for food and whether agree contractual prices are adhered to for the full four year term.

“This study raises serious questions about value for money and I look forward to the Wales Audit Office undertaking a thorough investigation.”

A spokesman for NHS Wales Shared Services, the organisation which buys goods and services, said: “NHS Wales procurement practice considers wider aspects than simply the lowest price; including, food safety, ethical & responsible sourcing and a high level of customer service to ensure that the contract fulfils our requirement to provide circa 7,800,000 patient meals per year ”.