Schools need quick access to money and support to cope with rising numbers of immigrant children from eastern Europe, teachers' leaders have warned.
Teachers in some schools were struggling to cope, especially in rural areas where staff have less experience of children who do not speak English.
Steve Sinnott, general secretary of the National Union of Teachers, and Mick Brookes, general secretary of the National Association of Head Teachers, gave evidence this week to a House of Lords committee on the economic impact of immigration.
Both praised the influence children from immigrant families had on schools.
Mr Brookes said: "The influx has been a breath of fresh air in schools. There are all kinds of success stories that have not yet hit the headlines."
But both union leaders expressed concern that teachers were not receiving the help they needed.
Mr Brookes said school admission procedures needed to be reviewed to ensure immigrant children had a fair chance of getting into popular schools.
The difficulties had been exacerbated by more immigrant families choosing to find work in rural areas, which do not have the infrastructure to cope, he said.
Mr Sinnott and Mr Brookes agreed it was difficult to say how much extra it cost to teach children from immigrant families, as their needs varied greatly.
Dr Janet Dobson, from University College London, who also gave evidence to the committee, said it was hard to put an accurate figure on the number of children from immigrant families entering UK schools.
She said it was likely to be in the tens of thousands rather than hundreds of thousands.