Ministers have unveiled proposals for a back-to-basics curriculum focusing on times-tables, spelling, reading and arithmetic - but a union leader warned it would lead to an unexciting "uniform education" for children.
The Government published new draft curricula for English, maths and science in primary schools which it says will help to boost standards.
Under the plans, pupils will be expected to memorise their times tables up to 12 by age nine, multiply and divide fractions by age 11 and begin to learn and recite poetry at five-years-old.
But the Association of Teachers and Lecturers (ATL) raised concerns that politicians had presented a "heavily prescribed curriculum" that will leave little chance for teachers to excite children and adapt lessons to suit their pupils.
ATL general secretary Dr Mary Bousted said: "The detailed programmes of study will lead to a uniform education, with next to no opportunity for teachers to excite children and adapt learning to suit their pupils in their local area, developing the skills they need for life, future education and work. ATL believes that the curriculum must help all children learn and develop."
Others said the new proposals contained some good suggestions, but warned that publishing details for the new primary curriculum is only half the picture.
Brian Lightman, general secretary of the Association of School and College Leaders (ASCL) said: "We welcome the emphasis on English and maths at primary as these are the building blocks of secondary education. The proposals appear to be a development of the current curriculum rather than a radical change, but it is clear that it will be more rigorous.
"There are still many unanswered questions about how it will look in the classroom and our full response to the primary proposals will depend what the secondary proposals look like."
Mr Lightman said it was "unfortunate" that the primary programmes had been published before a final decision had been made about the secondary curriculum. He said: "There needs to be continuity between what happens at primary and secondary and, without joined up thinking, many of the issues with transition to secondary school will remain."
The Department for Education (DfE) said that the new plans, which are being published for informal consultation before a formal process later this year, are designed to "restore rigour in what primary school children are taught in maths and science."