Scotland’s health boards spent almost £4 million on private security last year, according to figures obtained by the Conservatives.
The sum has risen each year from the £2.8 million spent in 2013/14, with the cost totalling £16.5 million over the past five years.
The figure varies between health boards, with NHS Grampian using no private security, and NHS Lothian spending almost £7 million over the period.
The Scottish Conservatives say the spending comes despite “repeated rhetoric” from the Scottish Government that it does not want private contracts within the health service.
The party, which released the figures following a Freedom of Information request, said some boards were being forced to protect disused sites, while others were spending millions “due to being locked into crippling PFI contracts”.
Chief whip Maurice Golden said: “The SNP never stops talking about how it despises the use of private companies when it comes to our NHS.
“Yet here we see, under its watch, spiralling costs when it comes to private security firms.
“Of course, these firms provide a valuable service to health boards and keep patients, staff and taxpayer-owned property safe.
“But it’s clear from this research that some major health boards don’t need to use private firms, which shows this is a choice rather than a necessity.
“It just means the next time the nationalists complain about private firms working in our health service, no-one will take them seriously.”
A Scottish Government spokesman added: “Any violence or aggression against NHS Scotland staff is unacceptable and we have policies in place to provide and continuously improve a safe working environment.
“We encourage all health boards to commit to supporting appropriate action against anyone who assaults a staff member, including criminal proceedings where appropriate.
“The majority of NHS services are provided by permanent NHS staff working on NHS contracts at NHS rates of pay.”