New grammar schools could take in just the cleverest 10% of children amid proposals that would make the system more elite, it has been revealed.
Education chiefs are also considering a "national selection test" to help prevent "test tourism", where parents enter their children for exams in different areas where they are considered easier.
The details of the Government's planned expansion of grammar schools emerged from notes of meetings between ministers, education advisers and the Grammar School Heads' Association (GSHA).
According to the GSHA document, Education Secretary Justine Greening said the response to the consultation on increasing selection, which closed in December, was not "an overwhelming flood of negativity".
Ministers reportedly still want to see the top 25% of pupils going to comprehensive schools, but the new selective schools will "probably have a narrower ability range, perhaps more like (the) top 10%".
The Government also wants to develop "coaching-resistant tests" and to "move away from focusing on social mobility to social reform", the document disclosed.
While there is a determination to address the needs of "JAMs" - families Prime Minister Theresa May said are "just about managing" - there has been an "over focus" on pupil premium, the extra funding given to schools to help disadvantaged children.
The document also said that admission policies to ensure children from lower-income households can attend grammars is "just one strategy".
New selective schools are likely to be opened as free schools, the GSHA note said, with the first likely to admit pupils in 2020.
There was no suggestion of how many new grammars schools could be approved.
The GSHA note said the ideas were discussed in meetings between some of its head teachers and Ms Greening, schools minister Nick Gibb, Department for Education (DfE) officials and Nick Timothy, Mrs May's joint chief of staff and former director of the New Schools Network.
Angela Rayner, the shadow education secretary, condemned the plans, tweeting: "Unbelievable grammar school heads have been given inside track on the Govt plans while our state schools & academies are left out in the cold.
"Tories will ignore the needs of all but a tiny minority of pupils The plans for yet more tests will appal everyone in the education world."
A DfE spokeswoman said: "Thanks to the Government's reforms over the last six years, there are now almost 1.8 million more pupils being taught in schools rated good or outstanding schools than in 2010.
"But we know there is more to do and that's precisely why we have set out plans to make more good school places available, to more parents, in more parts of the country - including scrapping the ban on new grammar school places and harnessing the resources and expertise of universities, independent and faith schools.
"The schools that work for everyone consultation closed on December 12.
"As the Secretary of State told the House of Commons on Monday, we have received several thousand submissions, which we are now going through. We will respond in the spring."