Oakengates Children's Centre, which has a nursery for two to four-year-olds, has been given an overall rating of "requires improvement" by Ofsted following an inspection in September.
A newly-published report said some staff did not support and challenge children well enough to reach their full potential because they lack a clear understanding of what children should be able to achieve at any particular age.
Phonics teaching was also described as "inconsistent" across the school.
The report said: "Teaching is not yet consistently good across the school.
"All staff have received good-quality training and support over the last year to help them improve their practice.
"Some improvement to the quality of teaching is evident but leaders continue to provide staff with training to further develop their skills.
"However, the improved practice is yet to have an impact on ensuring that all children make the progress of which they are capable."
Inspectors said some staff do not assess what children can do well enough and, therefore, do not provide learning activities which meet their needs.
Staff were also criticised for, on occasions, not giving children enough time to express their own thoughts and ideas.
Both the quality of teaching and outcomes for children were judged as requiring improvement by Ofsted, however it was rated "good" for leadership and personal development, behaviour and welfare.
At a previous inspection in 2013, the children's centre had been rated "outstanding" across the board.
Following the most recent inspection, there were some strengths outlined in the report.
The Ofsted report revealed that children are very well cared for and all staff ensure that children’s safety is of "paramount importance".
Inspectors said there were very positive relationships between staff and children.
The report continued: "The executive headteacher knows every aspect of the school’s strengths and weaknesses in detail.
"Her passion and determination has brought the staff together to work as a team.
"Consequently, she is successfully driving rapid improvements in the school.
"Governors hold all leaders to account for the school’s performance very well."
The nursery, based at The Place in Oakengates, has 101 children on roll.
It federated with Wrockwardine Wood Infant and Nursery School in April 2016.