Patients would be given a binding guarantee

Nationalists say no-one should wait longer than 18 weeks from GP referral to treatment by the end of 2011.

If elected at Holyrood, the SNP would give patients a legal right to be treated within a specified period and the right of redress if it is not met.

The proposal was endorsed unanimously by delegates at the SNP's spring conference in Dundee.

They also backed moves to make it easier for patients who receive sub-standard NHS healthcare to receive no-fault payouts, in order to prevent them having to go through the courts.

The SNP will now consult on the detail of the proposals, to be included in the party's manifesto for the 2007 Holyrood election.

In February Health Minister Andy Kerr said the NHS in Scotland had met the Scottish Executive's target of having no patient waiting more than six months for treatment by the end of last year.

Executive 'deception'

However, around a third of all patients waiting for NHS treatment in Scotland are not included in the figures as they do not have a waiting time guarantee.

Instead they are assigned Availability Status Codes (ASCs) for a range of reasons such as an inability to attend an appointment or due to a medical condition preventing treatment.

SNP health spokeswoman Shona Robison told the conference on Saturday that the party would introduce a Patients' Rights Act if elected to power at Holyrood next May.

"The SNP believes in cast iron rights for patients, not fiddled figures which this Labour-Liberal Democrat Executive has made a bit of an art form," Ms Robison said.

"I think Scotland has had enough of this deception and the SNP will introduce a transparent system, based on the needs of the individual patient.