An “ambitious” new law to tackle homelessness could fail unless councils are given more money to implement it, campaigners have warned, amid criticism it doesn’t do enough to “tackle the root causes” of Britain’s rough sleeping crisis.

The Homelessness Reduction Act is meant to reverse a trend of rising rough sleeping, which has gone up by 169% since 2010, as part of the Government’s bid to eradicate it by 2027.

Dubbed “the most ambitious legal reform in decades” by the Tories, the Act came into effect on Tuesday and imposes on councils the duty to take “reasonable steps” to stop people becoming homeless and broadens the definition of those at risk of it.

However, campaigners have told HuffPost UK they fear cash-strapped councils will be unable to meet the demands of the new legislation leaving “thousands of vulnerable people without support”.

Previously, councils only had to rehouse people who had young children or were somehow vulnerable. Now councils must help anyone who comes to them, including individual rough sleepers.

“Help” covers a broad range of actions and could mean helping someone negotiate with their landlord, finding them a hostel or an alternative long-term home.

The Government has put aside £72million for English councils over three years until 2020, but campaigners say this is too little to deal with the likely surge in cases. Brighton and Hove Council said it expected a 300% rise in its caseload.

Balbir Chatrik, director of policy at homelessness charity CentrePoint, told HuffPost: “Local authorities are struggling to juggle higher demands with significant central government funding cuts.

“We are very concerned that many councils will be unable to fulfil their new duties under the Act with the relatively small sum of funding provided.”

Polly Neate, chief executive of Shelter, told HuffPost the extension of councils’ obligations “can only be good news” but added: “There is reason for caution with this Act. 

“It heaps extra responsibility onto overstretched councils who are already struggling to cope, and it does not do enough to tackle the root causes of the crisis which are welfare cuts and a lack of social housing.”

Martin Tett, the housing spokesman for the Local Government Association, said: “Local authorities are currently having to house the equivalent of an average secondary schools worth of homeless children every month.

“Whilst they are doing all they can to help families facing homelessness, it’s essential that the new Homelessness Reduction Act duties on councils are fully funded.”

London Councils, which represents all 32 boroughs in the capital, has previously warned they need £77million a year to meet the requirements of the Act.

It said the shortfall “risks leaving thousands of vulnerable people without support”.

Sutton Council, in south London, expects its caseload to rise by 42% and noted in January that the £421,519 it was to be given between now and 2020 “falls significantly below the levels required”.

It said the Department for Communities and Local Government (DCLG) had assumed it would take a council employee two hours to draft a person’s action plan, as the Act requires, which sets out steps for the council and individual to take avoid them becoming homeless. The DCLG estimated would cost the authority £43,000 a year.

The council said this estimate fails to take into account the extra work staff would have to do to put the plan into action.

“The DCLG also fail to acknowledge that all action plans must be kept under review, regularly monitored, changes agreed and written up,” the council said in a report.

To cope with the bigger caseload, Sutton approved a plan to beef up its system to take more information from people who seek help to assess them earlier and draw up the provisional action plan.

It also plans to create a team of “targeted advisors” who each specialise in a different issue that can force people to leave a home. Where someone is threatened with eviction by friends or family, a visiting officer will visit the home to mediate between the parties.

Sutton estimated it would cost between £750,000 and £1.1million a year to execute its new duties.

Birmingham City Council told HuffPost it was doing to a “comprehensive review” of what temporary accommodation it has for people at risk of homelessness.

It added it had overhauled its staff training and IT to cope.

Councils are open to legal challenge if they fail to meet the requirements of the Act.

Greater Manchester mayor Andy Burnham, who has pledged to end rough sleeping by 2020 in the city, told ITV News the Government was “passing the buck” on the issue to local councils.

“They’re almost saying ‘If there is homelessness, it’s going to be your responsibility’. That isn’t fair,” he said.

Ben Reeve-Lewis, a housing advisor for councils, said some were “very well ahead of the game” but others were “struggling from the sheer numbers” they were going to have deal with.

He added the money allocated to councils, particularly in London, was a “pittance” that would not cover the new costs they could face, such as paying peoples’ rent arrears to ensure they do not become homeless.

A DCLG spokesman said: “This government is committed to tackling homelessness and rough sleeping. That’s why we’re investing over £1.2bn to help and have introduced the Homelessness Reduction Act – the most ambitious homelessness legislation in decades – which comes into force from today.

“The new law will help make sure councils, public services and the homelessness sector in every part of the country work together and intervene earlier, supporting people at risk and help those already homeless to find a home, regardless of whether they are a family or a single person.”