More children are starting school in Northern Ireland before they are toilet trained, a study has revealed.

There has been an increase in the number of children wetting or soiling themselves, the survey for the Association of Teachers and Lecturers (ATL) said.

Some 62% of primary school staff in the UK-wide review have noticed a greater problem.

Anne Millis, Northern Ireland president of ATL, said: "Having to deal with increased numbers of pupils who have not yet been toilet trained puts extra pressure on education staff when they already have enough pressure on them.

"Schools need to give staff clear guidance on how to deal with toileting accidents so that they know what they are allowed to do and who should be dealing with an incident."

The proportion of teachers noticing an increase in incontinence went up to 71% UK-wide amongst those working with three to five-year-olds - those in primary one in Northern Ireland. ATL surveyed 848 education staff working in state, independent and academy schools in the UK during October and November 2011.

Those asked felt that the main reason for the increase in the number of children wetting themselves at school was due to parents not toilet training their children before they start school.

Just under four in 10 (38%) respondents stated that their school has no written policy for dealing with childhood continence problems. Around 35% said their school has no written policy for dealing with childhood toileting accidents.

Some 38% of schools said they do not provide written information to parents of school starters about ensuring their child is toilet trained before starting school, while 36% said they do.

A Derry-based teacher and member of the senior management group said: "This is a major problem for us - over 45% of our nursery children are not toilet trained when coming into nursery when they are three years old. We also have children who soil and wet a great deal even in reception."