An agency doctor hired to do a week's work has cost the NHS more than £19,000, it has emerged.

Health chiefs in the Western Isles drafted in the consultant psychiatrist who spent 40 hours on duty and the rest of the time on call.

The £19,305.22 fee paid was revealed after a freedom of information request to the health board.

It said agency staff are only used when there are no other options to provide cover and "high" costs can be incurred when a gap has to be filled urgently.

NHS Western Isles' spending on temporary consultants increased from £452,000 in 2012 to £1.2 million last year, according to reports, while the number of consultants employed dropped from 43 to 36 over the same period.

The £19,000 paid to the consultant specialising in old age care included VAT and a fee to the agency.

A spokeswoman for NHS Western Isles said: "During a period of extended sickness absence in 2013, a consultant psychiatrist was hired from an agency to cover one week's annual leave for the remaining consultant.

"The locum consultant undertook 40 normal working hours and provided 128 hours on call for which the cost to the board was £19,305.22. This figure is the gross total paid to the agency and includes 20% VAT."

Health Secretary Shona Robison said: "We have a record number of consultants working in Scotland's NHS and boards are working hard to recruit even more. Workforce in the Western Isles is up 3 per cent under this government.

"When the use of agency staff is required, we have long-standing framework contracts in place which allow us to engage staff at nationally agreed rates of pay.

"These contracts are reviewed on a regular basis."