The age limit for free bus passes could be raised as a consultation on the benefit gets under way.

Transport minister Humza Yousaf has issued a call for views on proposals aimed at making the concessionary travel scheme affordable in future.

More than 1.3 million over-60s and disabled people benefit from the free bus pass, accounting for about 145 million journeys each year or a third of all those made in Scotland.

The scheme is facing a £9.5m cut in the 2017-18 draft budget despite rising numbers of older people.

Yousaf insisted passes would not be taken away from those who already benefit or are due to obtain one before the changes come in.

Labour said the SNP has "no mandate" to make cuts to the bus pass budget as no such policy was in their manifesto for the 2016 Holyrood election.

The new consultation looks at whether the age of eligibility should be raised in one go or gradually to bring it into line with the state pension age, which will be equalised for men and women in 2018.

The government is also considering introducing free bus travel for modern apprentices and providing free companion travel for eligible disabled children under five.

Yousaf said: "The Scottish Government is committed to providing free bus travel to older and disabled people, and no one who has a bus pass will lose it.

"People are living longer, staying healthy longer and staying in work later in life and we aim to ensure that access to the benefits of the bus pass goes to those who have greater reliance on free bus travel.

"We keep the scheme under review to ensure that it continues to meet this objective and, as part of this process, the consultation gives us the opportunity to find out how the people of Scotland see the future of the scheme."

He added: "We will listen carefully to the views given in the consultation and take account of them in deciding whether any changes need to be made to the scheme at this time."

Scottish Labour's transport spokesman Neil Bibby MSP said: "A Labour government introduced the free bus pass, allowing older people and disabled people the freedom to travel where they choose.

"We will fight the SNP's cuts to the bus pass. The SNP have already cut £10m from the bus pass budget and now they are consulting on plans to cut back eligibility and restrict the number of people who will get the free bus pass in future.

"It is now absolutely clear that the SNP have been not been honest with voters about their intentions."

Bibby added: "In their 2016 manifesto the SNP promised that the bus pass would continue and said nothing about cutting it back."

"They have absolutely no mandate to make these cuts. To do so would be a betrayal of voters' trust.

"Humza Yousaf should go and read his own 2016 manifesto and ditch his plans."

The consultation will be available on the Transport Scotland website until November 17.