Teachers banned for incompetence in Scotland, Wales and Northern Ireland will still be allowed to work in England after its General Teaching Council (GTC) is abolished next year, if Government plans go ahead.
The new regulatory body for teachers in England - the Teaching Agency - will not recognise sanctions imposed in other UK nations regarding teacher competence.
The agency will also ignore reprimands and other conditions placed on teachers for misconduct. The only sanctions it will register are bans for misconduct and "relevant" criminal convictions.
Currently, any teacher who has been prohibited from teaching in Wales, Scotland or Northern Ireland on any grounds is normally barred from teaching in England and vice versa.
Other sanctions applied in Wales, Scotland and Northern Ireland will not be recognised in England because the Teaching Agency will only have power to make prohibition orders.
In response, GTC Wales and GTC Scotland have introduced tougher registration procedures for teachers who move from England. They feel there is a risk of "unsuitable people" now being able to work in their countries.
English teachers who want to work in Wales and Scotland will have to give details of any disciplinary action they have faced in order to register.
Hayden Llewellyn, registrar and deputy chief executive of the General Teaching Council for Wales, said the Department for Education was taking a "gamble" and that the changes would lead to "major weaknesses" and create "very significant risks".
"We are putting in place the most robust system we can, but there is still an increased risk that unsuitable teachers will slip through the net because of decisions taken across the border," he said.
He added: "The proposals suggest that professional misconduct or criminal offences short of the most serious ones are something the Government thinks parents do not care about."
Under the new system, ministers want individual schools in England to deal with competency and conduct issues. The Government has also proposed speeding up the process by which incompetent teachers can be fired.
Teaching unions and associations in England have also expressed concern.
Alison Ryan, policy adviser for teaching union the ATL, said: "Parents will be rightly concerned by this and we would also have serious concerns if details about people who shouldn't be in the classroom, or who need particular support before they should go back into teaching, are not transferred across borders."
Malcolm Trobe, policy director of the Association of School and College Leaders, said the Government had not recognised the "significant movement" of teachers across UK borders.
"There should be an agreed system across all four nations in order to ensure teachers are treated fairly," he said. "It's now up to the Government to sort this out. This shows the nonsense which can be caused when ministers make decisions too quickly. This is clearly not a rational system."
A DfE spokesman said: "We want to have a grown-up relationship with schools and trust professionals to tackle issues of competence and conduct effectively.
"The responsibility, as ever, will be on employers to satisfy themselves that the teachers they employ are competent and capable through a process of open and honest references."