The First Minister and Health Secretary have apologised to patients who have faced delays for treatment as a result of winter strain on the health service.

Nicola Sturgeon said NHS Scotland was dealing with ''exceptional'' pressures but was coping despite difficult circumstances.

Health Secretary Shona Robison defended the Scottish Government's flu vaccination programme after ministers were accused of failing to act on warnings.

Latest figures show the number of people suffering from flu in Scotland has more than doubled compared to the same time last year, with about half of NHS boards reporting significant ward pressure as a result.

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Ms Sturgeon told BBC Radio Scotland's Good Morning Scotland programme: ''I would apologise unreservedly not just during the winter but at any time of the year to any patient who is not seen as quickly as we would want them to be seen in the NHS or who doesn't get the treatment that they have a right to expect.

''We have seen exceptional pressures this winter largely due to the increase in flu cases but also, particularly in the period immediately before Christmas, weather-related pressures, but the hard work, the incredible hard work, the incredible teamwork, of the staff of the NHS - and I want to take this opportunity to thank each and every one of them - means that our NHS is coping in very, very difficult circumstances."

Ms Robison, speaking during a visit to Perth Royal Infirmary's A&E department, said: "Any patient waiting longer than they should to be seen and treated within the NHS, I would apologise for that, but I think the public understand that we are in exceptional circumstances here and I have had lots of messages from the public saying staff, in the face of huge pressures and challenges, have done a tremendous job."

Provisional figures suggest uptake of the flu vaccine is similar to last winter.

Ms Sturgeon said early information suggests rates have increased slightly among NHS staff, with less than 50% vaccinated last year.

The Scottish Conservatives have argued ministers should have done more to boost uptake.

Ms Robsion said: "There was a really robust, big campaign to promote vaccination, in the same way as we have done in previous years, not just for the public but health and social care staff as well.

"We can't force people to get the vaccination, all we can do is promote and encourage, and we used every communication channel possible to get that message across."

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Winter pressures are expected to be reflected again in A&E waiting-time figures, the Health Secretary added.

The number of patients seen within the target four-hour waiting time was well below the 95% target in the weeks before Christmas.

Weekly statistics due to be published on Tuesday will cover the period between Christmas and New Year.

Ms Robison said: "The A&E figures will remain very challenging indeed and people are working very, very hard to keep patients safe and, of course, people within A&E will be seen and treated and discharged as quickly as possible.

"The week we have just seen ... was one of the most challenging weeks.

"Of course our A&E performance prior to that has been the best in the UK for over two years, so A&E performance was very, very strong, but it has been impacted by these winter pressures and that will remain the case for the short-term while they get into recovery mode."

Conservative health spokesman Miles Briggs said Scotland was failing to meet the target of having half of all NHS workers vaccinated against the flu while in England almost two-thirds (63%) were vaccinated.

The Tory MSP said: "Nicola Sturgeon tried to put a gloss on the SNP's response to the winter flu crisis this morning but failed to explain why so few NHS staff in Scotland have been inoculated.

"Last year, only 35% of healthcare workers were vaccinated against flu - below the target and well below figures elsewhere in the UK.

"The impact of this is devastating - it means doctors and nurses unable to come into work and patients suffering further delays as a result."

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Labour health spokesman Anas Sarwar said an apology from the First Minister "just isn't good enough for patients and NHS staff failed by the SNP government this winter".

He said: "These were not unforeseen circumstances. Our NHS faced a similar crisis last winter yet the SNP overtly failed to make the preparations necessary to avoid another winter meltdown.

"In fact, things got so bad this year that in Lanarkshire backroom office staff had to volunteer to help GPs and hospital staff cope, such is the scale of the under-staffing in our health service.

"A real apology would be backed up with real action but Nicola Sturgeon offers nothing except warm words. Scotland's patients and NHS staff deserve better in 2018."