At a meeting with Cabinet Secretary Richard Lochhead, the Scottish Tenant Farmers' Association stressed that the long-awaited report from his Rent Review Group, released in December, had failed to deliver for tenant farmers.
The STFA warned that unless control measures were put in place, rents would escalate, damaging the viability of family-sized farm businesses, particularly if the open market continued to be used as a benchmark for rents.
STFA chairman Angus McCall said; "We expressed our disappointment that the Rent Review Group has failed to recognise the dangers of an open market driven rent system which depends on what the Group's chairman referred to as the 'black art' of valuation.
"Our view remains that legislation is needed to reform section13 of the 1991 Act which sets out the rules on rents. However, in the short term, it is now imperative to draw up stringent guidelines for rent reviews which will put a financial viability health check at the heart of the review process. This must be backed by an enforceable code of practice.
"With rounds of rent reviews marred by allegations, counter allegations and overshadowed by the spectre of litigation, tenants feel there is nowhere to turn," said Mr McCall.
"Last minute pressure mounts as rent term date approaches. The rental figure in dispute may not even be great, but faced with the threat of the Land Court and the potentially enormous costs associated with it, tenants are under pressure to back down and give in. This makes rent reviews very difficult and stressful for tenants and rents inevitably get wracked ever upwards by this process of attrition.
"Vulnerable tenants need to have trust and confidence in a properly accountable system where a fair rent can be settled quickly at an affordable cost." said the tenants' leader.
Mr McCall suggested that the market could not be reliably self-regulating, as land agents who succeeded in agreeing higher rents were likely to find their services more sought after.
"It is not difficult to predict the effects of this financial pressure on the viability of family farming businesses. It will hasten the steady decline we have already witnessed of these tenancies which currently contribute to the rural economy and rural communities of Scotland as government statistics bear out.
"This must be addressed and the recommendations of the RRWG of self regulation in rent reviews have been less than helpful," he said.
"The next round of rent reviews is only a few months away and we have impressed on the Cabinet Secretary the need for urgency if measures are to be put in place in time to give tenant farmers the confidence that they will get a fair deal."