NEW concerns that Scotland is facing a demographic timebomb have been raised after experts predicted the number of over-75s would nearly double in the next 25 years.

The National Records of ­Scotland data suggests the country's population will rise by almost half a million people, with part of the increase because Scots are expected to live longer.

It said an 86% rise in the number of over-75s would contribute to the overall population swelling by 9% to nearly 5.8 million by 2037.

The document also states the number of those of pensionable age will go up by more than one-quarter in the next 25 years, while those aged between 60 and 74 would also rise sharply.

Scottish Conservative health spokesman and deputy leader Jackson Carlaw MSP said: "While it's welcome that so many people will live longer, healthier lives, we have to be ready to meet the consequential resource demand on public services and our health service in particular.

"Our NHS and councils are already at full stretch coping with Scotland's ageing population, so the Scottish Government needs to urgently articulate in detail how we will all need to adapt as the issue becomes ever more acute."

But Age Scotland added: "An ageing population is something to be celebrated rather than feared as older people make a huge contribution to Scottish society; as active citizens, carers, workers and contributors to our culture.

"Of course there are challenges, but these can be met by investing more in services that support healthy active ageing and ensure people don't become lonely and isolated as they get older."

Labour pensions spokesman Gregg McClymont MP said Scotland was facing a pensions timebomb. He said: "This report is further evidence of the risks to Scots' pensions posed by leaving the UK. The figures are clear; there is a pensions time bomb facing Scotland as we don't have the working age population to pay for the UK level of state pension.

"The time for denying reality and hoping difficult questions can be ignored is over for the SNP. Whether it's on pensions, currency, EU legal advice or welfare, their head in the sand approach isn't good enough."

The figures suggest there will be an extra 200,000 people in Scotland by 2022.

Some 28% of the population rise expected between 2012 and 2022 is attributed to a natural increase (more births than deaths) with the other 72% due to assuming continuing inward net migration.

National Records of Scotland experts admit the assumption made in their projections on net migration may be wide of the mark as they do not take account of any potential policy changes that may come about, for instance, from an independent Scotland.

While the number of children aged under 16 in Scotland will rise by 4% in the next 10 years from 910,000 to 950,000, those aged 75 and over will swell from 420,000 to 530,000.

Between 2012 and 2037, the ­average age in Scotland is expected to increase from 41.5 years in 2012, to 42.3 years mid-2022 and 44.3 by mid-2037.

Meanwhile, the population of England is expected to rise by 16% between 2012 and 2037, 10% in Northern Ireland and 8% in Wales.

A Scottish Government ­spokesman said: "All developed countries - including Scotland and the UK - face increasing pensioner populations. As our pensions paper makes clear, the increase in the Scottish dependency ratio over time, compared to the UK, is largely driven by slower growth in the working age population. Therefore, Scotland's demographic challenge is to increase its working age population over the longer-term as a share of overall population."