Government claims that homelessness numbers have fallen by a fifth since last year should be taken with a health warning, says housing charity Shelter.
Councils are now required to have a strategy to reduce homelessness
It pointed to a study showing 63% of council staff felt pressured to bend the rules to reduce the numbers of people they accepted as homeless.
The majority of the 60 officers quizzed said that pressure was coming from the Office of the Deputy Prime Minister.
But the department said it had seen no evidence of rules being broken.
Government figures published on Monday showed homelessness acceptances - when local authority officers judge someone to be officially homeless - had fallen by nearly 7,000 compared with the same period last year.
Welcoming the statistics, Housing Minister Yvette Cooper put the fall in homelessness numbers down to new programmes to tackle the issue.
"This is very welcome progress. It hasn't happened by accident. New local strategies and £200 million of investment in preventing homelessness are making a real difference.
"Simple things like lending families the money for the rent deposit they need can stop them being stuck without a home."
Shelter Director Adam Sampson said he he welcomed "renewed efforts to tackle homelessness".
But, he added: "Unfortunately we have to reserve applause on today's figures until we can be sure that a fall in homelessness is coming about because those in need are being given better housing solutions.
"A nationwide lack of social housing means the only real option open to councils is to "prevent" homelessness.
"In its best form, which we support wholeheartedly, this can mean working with people at risk to ensure they do not fall into the trap of homelessness - however, many staff themselves have expressed reservations that they are effectively bending the law in order to avoid accepting people as homeless."
The ODPM put the improvements down to government schemes, such as the rent deposit schemes which allow people to find good quality rented accommodation in the private sector and mediation services to resolve disputes.
But the Shelter survey for its national magazine, Roof, cited example of officers bending the rules or "gate-keeping".
These included asking applicants for an unreasonable burden of proof like the last five years of their housing history, detailed medical records or an eviction letter.
It also cited the case of a teenage victim of domestic violence whose application was refused after the officer called her abuser to ask if she could still live with him.
Ms Cooper said the fall in homelessness was "welcome progress"
The Housing Law Practitioners Association told the magazine that the decision-makers had been "forced into a culture of adverse decision-making" by the lack of affordable housing.
A spokesman for the ODPM said: "Suggestions that this is about avoiding helping people are completely wrong.
"It does a huge injustice to the positive action that many local authority and voluntary agencies around the country are taking to tackle homelessness.
"We have not seen any substantial evidence that this is happening and reject findings of this survey."