Around a third of parents do not know if their child is being taught by a qualified early years teacher, according to a new poll.
The majority of mothers and fathers would rather their child was taught by someone who specialises in early years education, while many think that ministers should ensure there is a qualified teacher in every nursery, according to the Save the Children poll, carried out by YouGov.
Out of 944 respondents with children aged five and under, 34 per cent did not know that their son or daughter's nursery has a teacher who is trained to degree level.
Around half said they would be worried about sending their child to an establishment with no qualified early years teacher.
And around seven in 10 (71 per cent) said they would rather send their pre-schooler to a nursery with a qualified teacher than a nursery that does not have one.
Approximately three quarters (74 per cent) said that the government should ensure that every nursery has a qualified member of staff.
Save the Children said it had calculated that by 2020, around 800,000 young children will be at risk of not reaching a good level of development at age five.
They also found that of those who start school behind, around a quarter are likely to remain behind in English by the time they reach secondary school, with around a fifth behind in maths.
Chief executive Kevin Watkins said: "It's just not acceptable that in this day and age, so many children in England are falling behind before they even set foot in primary school - leaving them at risk of staying behind throughout their school years and into the world of work.
"Nurseries do an incredible job nurturing our children, but financial constraints are leaving many of them struggling to hire the qualified early years teachers who help give children the skills and confidence they need to learn and grow.
"The evidence clearly shows the huge and transformational difference early years teachers can make for children.
"That's why we're calling on the government to ensure every nursery has a qualified teacher. It's an investment we must make to help every child reach their full potential."
The findings come just days after researchers suggested that children who have access to a qualified teacher at nursery do only slightly better at age five than their classmates.
A new study concluded that a youngster's educational achievement at the end of their reception year is only very slightly higher if they have been taught in a nursery with a teacher trained to graduate level.
Russell Hobby, general secretary of school leaders’ union NAHT, said: “The presence of trained teachers in early years makes a significant difference, particularly for those children growing up in poverty. We need more qualified teachers working in early years and, crucially, the settings need the funding to be able to employ and train them.
“Last year we welcomed a quality supplement, encouraging early years providers to employ highly qualified teachers, but more funding is needed over the next five years in the most deprived areas to enable recruitment and retention of early years teachers.
“Early years is the right priority for investment for a government genuinely interested in social mobility and tackling the disadvantage gap.”
James Bowen, director of middle leaders’ union NAHT Edge, says: “Quality is key in early years provision, and this report shows that a highly skilled workforce makes a proven difference to children’s early development. Whilst qualifications alone don’t guarantee excellent practice, it is fair to say that the higher the quality of the workforce overall, the better deal children are likely to get.
“But early years settings can only offer high quality care and provision if they are properly funded, have highly skilled practitioners and if they are afforded the recognition they deserve.”
A Department for Education spokesperson said: “All nursery settings are already required by law to employ staff who are qualified to support the learning and development of young children. There are record numbers of nurseries, pre-schools and childminders rated as ‘Good’ or ‘Outstanding’ and the proportion of children reaching the expected learning and development standards continues to rise.
“We are investing over £6 billion per year by 2020 into childcare, more than any other government, and creating a workforce strategy to attract, retain and develop the very best staff to the sector. We are also funding early years initial teacher training routes to help increase the specialist graduate workforce.”