Pre-school Berliners are to be given free childcare in a move expected to make the German capital even more attractive to young families.

The city is the first of Germany’s 16 states to abolish fees, in a country where the cost of sending children to kindergarten differs vastly depending on where you live.

“Berlin has kept its promise and has resumed its policy to be family-friendly,” said Sandra Scheeres, the Berlin senator for youth and a member of the Social Democrats.

But even as many parents were celebrating the move, which will save them hundreds of euros a month, critics were warning that the apparently generous gesture threatened to sink the city’s creaking childcare infrastructure.

Problems such as underinvestment, underpaid carers and a lack of kindergarten places are likely to worsen as millions of euros are diverted to pay for the scheme, according to the Greens, who are among its main critics.

The abolition of fees in Berlin, where under means-testing parents had been paying on average less than 2% of their net income for a kindergarten place, according to a recent study by the Bertelsmann Foundation, has triggered a national debate about discrepancies between states.

Parents in the northern state of Schleswig-Holstein pay just under 10% of their net income on kindergarten fees.

The Berlin government began to cut fees 11 years ago, startingby abolishing fees for children in their last year before school, and ending with cutting fees for the under-ones – about 15,800 children.

Parents will have to pay a €23 (about £20) monthly fee for food and a monthly fee of €90 to cover extra activities such as sport and music lessons.

Nadine, a mother of two children aged 18 months and four years who attend a kindergarten in the northern district of Prenzlauer Berg, said she was delighted by the move. “I’m bowled over – this amounts to a saving of around €400 a month for me,” she said.

However, she voiced her concern for the long-term welfare of children in Berlin. “The danger is the politicians will now think they can turn their attention to other things, but there are lots of issues of concern like the difficulty of getting a kindergarten place, the low pay of the carers, and the fact that there are not enough of them,” she said.

About 900 extra carers will be needed to cover the next wave of children starting kindergarten. It is thought that many parents would not have sent their children if they had had to pay. Experts are predicting that many families are likely to want to move to Berlin to take advantage of free childcare.

Ten other states have also agreed to cut fees, under a nationwide drive to decrease the burden on working parents and improve education standards that was agreed byAngela Merkel’s coalition government. It is hoped the move will encourage children with immigrant backgrounds to attend kindergarten to improve their language and social skillsand improve the education chances of children from poorer backgrounds.

There also plans to improve the child-carer ratio, which differs wildly from one carer to three children in some states to one carer to seven children in others.

“Which is why offering free places only makes sense if there is a massive investment in the personnel,” education expert Anette Stein of the Bertelsmann Foundation told German media.