They fear fewer flats would be available for short-term rent under proposals drawn up by the Scottish Government.
And there are concerns landlords will be forced to abandon the lucrative festivals market if they are banned from repossessing properties from tenants unless they intend to sell or live in them.
That could push prices up as other landlords look to cash in on the lack of accommodation.
Housing charities and campaigners, however, shot down the claims and insisted the biggest overhaul of the legislation for 25 years would benefit tenants and landlords alike.
David Alexander, managing director of DJ Alexander, said: “In Edinburgh, many landlords who let out flats to student tenants for nine months then take a summer break, during which the property is let to Festival-goers for a month.
“However, under the proposals being considered by the government, the tenant could simply turn around and say, ‘I have security of tenure, I like it here and I’m not moving’ and the landlord could do nothing about it.”
Launched by Housing Minister Margaret Burgess last October, the government paper, New Tenancy for the Private Sector, which is currently out for consultation, aims to give tenants greater security.
Under the proposals, any required “notice to quit” period will be linked to how long the tenant has lived in the property and the “no fault” clause, which allows landlords to reclaim their property simply because a fixed rental term has ended, would be scrapped.
Adam Lang, head of communications and policy at Shelter Scotland, said: “That any letting agent should raise concerns about not being able to remove people from their homes so they can turn a high profit during the Edinburgh Festival season, shows exactly why reform of the private rented sector is badly needed. Despite the growing number of people – particularly families with children – now living in the private rented sector, it is all too often viewed as short-term housing and not the long-term homes Scotland desperately needs.
“The new tenancy proposals are aimed at rebalancing the relationship between tenant and landlord by improving the security of tenure for private renters while safeguarding the rights of lenders, investors and landlords.
“These proposals will help to make the sector fit for purpose and fair for all.”
Alyson Macdonald, of the Living Rent Campaign, said the market value of a rented flat in Edinburgh was hugely inflated during August because Festival visitors will pay four or five times as much as tenants who live in the city year round. She said: “Rented properties are already very lucrative investments for landlords [who] don’t need the extra bonus of sky-high Festival rents to make ends meet.
“We would suggest landlords concerned student tenants won’t move out over the summer try offering to compensate them for the inconvenience and finding storage for belongings.”
John Blackwood, chief executive of the Scottish Association of Landlords, said: “We would urge the Scottish Government to reconsider additional protections for tenants without harming investment in the private rented sector.”