The buy-to-let market is still booming but landlords and tenants should beware as complaints about tenancy contracts are also on the increase.

The warning came from Birmingham property consultants, Curry & Partners, who are advising landlords to provide clear and fair contract terms if they want to maxim-ise their property investment.

Richard Crathorne, a partner at Curry's Sutton Cold-field branch, and a member of the Association of Residential Letting Agents, said: "Despite the fact that the Chancellor has killed off residential investment using self invested pension plans, landlord interest in property is still buoyant.

"Recent ARLA research, the widest regular survey of investors in the private rented sector, highlighted that more than two thirds of investor landlords expect to enlarge the size of their portfolios during 2006. At the same time, complaints to the Office of Fair Trading about unfair contract terms between landlord and tenant are growing. The worry is that many tenancy agreements are simply cobbled together and do not comply with latest revisions to the regulations governing consumer contracts.

"This, of course, is leaving landlords exposed to the possibility of expensive and time-consuming legal action."

Curry & Partners advises that landlords and tenants should check documents carefully before signing them.

Mr Crathornbe said: "A term is considered unfair if it causes a significant imbalance in the parties' rights and obligations under the contract, to the detriment of the tenant.

"Landlords should not limit their liability by transferring their legal obligations to their tenants, nor should they impose potentially excessive penalties for failure to meet the terms of the contract. Excessive rates of interest on late rent payments, for example, will not be tolerated by the OFT.

He added: "Landlords need to be aware that if a clause is not considered fair it may be void and unenforceable. The contract may then be worth no more than the paper it is printed on." ..SUPL: