The tenant rights initiative was welcomed by housing campaigners yesterday, but the Irish Property Owners' Association said the Government's plans were "over the top".
Although Opposition parties welcomed the legislation, they said it did not go far enough to protect tenants.
The housing organisation Threshold welcomed the changes, but said the Government should do all in its power to ensure the law was enforced.
Its chairwoman, Ms Aideen Hayden, disputed claims by the Minister for the Environment, Mr Cullen, that rents were falling in the market.
Mr Cullen cited anecdotal evidence. But Ms Hayden said the only rents that were falling were those for apartments occupied by young professionals.
She said that Threshold would propose amendments to the legislation and said the Government should do all in its power to enforce the legislation.
Calling for very serious sanctions against those who flout the law, she said that Private Residential Tenancies Board would have to take a strong line against offenders. She said the legislation should protect the most vulnerable tenants, especially those receiving State assistance to pay their rents.
However, the Irish Property Owners' Association said it was very concerned about "bias against landlords" in the legislation.
Its information officer, Mr Fintan McNamara, said the new system of registration would create a bureaucratic nightmare for landlords.
The legislation should have concentrated on the needs of lone parents, families with school-going children and the elderly.
"Landlords will see this as the thin edge of the wedge," he said. They feared that more stringent measures would be introduced in the future.
"We feel this has gone too far. It's over the top."
Welcoming the initiative, the Fine Gael environment spokesman, Mr Bernard Allen, said the reform was overdue. He said the legislation should ensure security for tenants and protect the rights of property owners.
Mr Allen said: "The regulations regarding the registration of rented accommodation have been ignored and the inspection by local authorities of rented accommodation and the enforcement of building and fire regulations has been very poor, to say the least."
Also welcoming the legislation, Labour said it would table amendments to shift the balance further in favour of tenants.
The Green party environment spokesman, Mr Ciaran Cuffe, said the Bill did not go far enough. He said rent increases should be capped at 5 per cent above inflation to strike a balance between the rights of tenants and landowners.
The Sinn Féin TD, Mr Arthur Morgan, said rent increases should be index-linked and not market driven. "The failure to address rent regulation and issues regarding affordability will seriously undermine the security of tenure provisions," he said.
The Socialist Party TD, Mr Joe Higgins, said the Bill failed to address "extortionate rents" charged by landlords.
Criticising the measure to set rents at market rates, Mr Higgins said that the "entire control over the levels of rent is placed exclusively in the hands of the landlord class".