The number of new hospital outpatients waiting more than 12 weeks for treatment has increased.

It comes despite a Scottish Government "guarantee" that patients should be treated within that timeframe.

Newly released figures from the NHS show that in March this year 32,961 new outpatients had to wait longer than 12 weeks, compared to 19,854 in March 2015 and 7445 in March 2014.

The Treatment Time Guarantee (TTG) came into force in 2012, stating that eligible patients must receive treatment within 12 weeks of the treatment being agreed.

In March this year, 88% of new outpatients were seen within the 12-week period, down from almost 97% two years previously.

Health secretary Shona Robison said "more clearly needs to be done" to meet the "demanding" targets the Scottish Government had set.

She highlighted that more than one million patents have been seen within the 12-week period since the TTG was introduced in 2012.

Ms Robison said: "Health boards across Scotland continue to deliver some of the lowest waiting times on record, with 1.1 million patients treated within our 12-week treatment time guarantee since it was introduced in October 2012.

"However, more clearly needs to be done to maintain and improve performance to meet the rightly demanding targets we have set.

"Patients should expect nothing less. That's why we have provided recent investment to ease pressure and set out long terms plans to ensure our NHS is fit for the future.

"This includes our commitment to investing £200m to create five new elective and diagnostic centres across the country, as well as expand services at the Golden Jubilee Hospital.

"These centres, which will carry out procedures like hip, knees and cataracts operations, will allow people to be treated more quickly for planned surgery.

"This will help the NHS meet increasing demand from a growing elderly population, taking pressure off unplanned and emergency treatment."

Scottish Labour said patients were losing out due to increasing pressure on the NHS.

The party's health spokesman Anas Sarwar said: "With only a third of NHS staff believing that there are enough of them to do their jobs properly it is little wonder that patients are losing out on legal guarantees the SNP promised them.

"The SNP made a series of big promises on our NHS but all we have seen is increasing pressure on staff, missed targets for patients and a sense of crisis management rather than a plan for the long term.

"We need to give our health service, established in the 1940s, the resources it needs to face the challenges of the 2040s.

"Instead the SNP plan huge cuts to the budgets of councils which deliver social care which just piles more and more pressure onto our hospitals.

"This is not a sustainable long-term plan for our health service."