Childcare is typically more expensive for those under the age of two, as a higher ratio of staff members to children is required.
The Government insists it is confident that the roll-out will be delivered on time, and the Prime Minister said on Monday that despite some “practical issues” the project will go ahead as planned.
Mr Sunak said: “We are excited about our plans to expand childcare in a way that has never been done in our country before.
“Many families have been able to sign up and it’s all working fine, but there are some practical issues that certain families are facing. I just want to reassure all of those people that those issues are being resolved as we speak, all of those families will get the childcare that they are eligible for.”
Problems with the scheme began when the Department for Education was forced to fix a mistake it made while allocating money to local authorities to fund nurseries, leading to processing delays.
The department is also facing a £120m budget shortfall after underestimating the cost of the first year of the project.
Industry leaders said it would be “financial suicide” for providers to commit to offering places before they knew how much funding they would be offered.
Neil Leitch, chief executive of the Early Years Alliance, a charity that represents 14,000 nurseries, pre-schools and childminders, said: “The Government cannot expect providers to offer places to parents from April without telling them what they are going to be paid for it.”
The sector has faced recruitment struggles, and could struggle to attract enough staff to provide enough places, Mr Leitch said. He explained that there had been a significant increase in closures over the past year, especially in more deprived areas, which had increased the pressure on remaining nurseries.
The Telegraph understands that the Department for Education is planning a recruitment drive for nurseries before the further expansion of the scheme in September.
A Department for Education spokesman said: “We are rolling out the single largest expansion in childcare in England’s history, ensuring working parents receive 30 hours of free childcare a week, starting at nine months old all the way up to their child starting school.
“Thousands of parents are accessing codes and securing places every day, and we are confident in the strength of the market to deliver the offers. We are automatically sending codes for any parents who can’t get one through the system until mid-February to make sure no parent misses out on the opportunity to get a code and claim their space.”