Vulnerable babies are regularly turned away from Scotland's specialist infant care units because of serious staff shortages, a leading charity warns today.

A report from Bliss has revealed that on any day during two-thirds of last year at least one of the nation's 16 units was closed to new admissions, with almost half shutting their doors at some point.

As a result, newborns and their parents have been forced to travel hundreds of miles for lifesaving treatment, increasing the risk, stress and cost for devastated families.

The charity also found that minimum staffing levels in neonatal intensive care were not being met due to the service being so overstretched, prompting criticism that infants are getting a second-class service compared to older children and adults.

It is the third Bliss report in just more than two years to highlight the worrying problems in the crucial service, which admits around one baby every hour.

Just 12 specialist neonatal nurses were recruited across the whole of Scotland between 2006 and 2007.

Bliss chief executive Andy Cole yesterday called on the Scottish Government and health boards to act now to recruit and retain an extra 140 neonatal staff, which it says are needed to meet growing demand for care.

Speaking before the official launch of the report at the Scottish Parliament, Mr Cole said: "We have to ask why, after so many years of calling for action over this, it has yet to be delivered.

"We are very concerned that units are working very much over capacity and that it is only due to the extra work by doctors and nurses that the system is holding together as well as it is.

"The minimum staffing level in neonatal intensive care of one nurse to one baby is rarely met. Generally they receive 1:2 care, which is roughly half what you get for adults and children.

"Increasingly units are having to close because of a lack of staff, putting extra strain on families who have to travel often long distances at what is already a very difficult time.

"Rates of premature and low-weight babies are slowly rising and there is an inherent risk in moving babies, although Scotland's transport system is by far the best in the UK.

"We are calling on the government and health boards to act now and fund staffing, developing a long-term plan to recruit and retain neonatal nurses."

The call was echoed by the Royal College of Nursing union. Theresa Fyffe, Director of RCN Scotland, said: "It is simply unacceptable that babies are sometimes transferred between neonatal units because of a lack of staffed intensive-care cots.

"As well as getting the numbers of neonatal nurses right, it is critical that the skills, experience and expertise of the whole nursing team are appropriate for the levels of dependency in each neonatal unit."

There are around 550 neonatal nurses in Scotland, compared with the 700 that Bliss says are needed.

The Scottish Government defended its record yesterday, stating that it was already acting to strengthen provision of neonatal care across Scotland, including funding training for 20 of the highest level of specialist neonatal nurses.

Public Health Minister Shona Robison said: "While we agree with Bliss that services should be offered locally wherever possible, the highly specialised and unpredictable nature of neonatal care means it is sometimes vital to transfer babies or pregnant women."

She added that a sub-group of the Maternity Services Action Group was conducting its own review of neonatal services in Scotland.

NHS Scotland is also developing a new way of working out neonatal staffing levels, based on measurements of actual activity within units.

In 2008-09, the government invested a further £100,000 in neonatal nurse education.