A report published this week by London mayor Sadiq Khan found that last year, just 61 per cent of eligible two-year-olds took up a free early education place in the capital compared with 72 per cent nationally.
There are also widespread differences across boroughs. In Tower Hamlets less than half (47 per cent) of disadvantaged two-year-olds are accessing their free entitlement, while Sutton has exceeded its allocation of free spaces.
To ensure more access free hours, Khan is handing 11 organisations grants of between £8,000 and £15,000 to boost awareness of the entitlement among disadvantaged families.
The offer entitles two-year-olds with experience of care, in families living on benefits, or with a special educational need or disability, to 15 hours of free childcare a week.
Groups involved in the awareness-raising drive include Family Lives, which supports more than 400 low-income families with complex needs in Westminster, South London Tamil Welfare Group and Minik Kardes nursery, which helps Turkish- and Kurdish-speaking families in Hackney.
Meanwhile, Khan has also made £250,000 available to fund an Early Years Leaders programme in London.
Through the programme the National Day Nurseries Association (NDNA) will work with 30 coaches who will help 90 childcare practitioners to develop their management skills.
"All types of childcare are under pressure currently due to underfunding of government places, so nursery leaders need all the support they can get, said NDNA chief executive Purnima Tanuku.
"This programme aims to improve the quality of provision offered to young children. We know that high-quality early years education is the best way to improve life chances for all children, particularly those from disadvantaged backgrounds. The best way to do this is to upskill early years practitioners and managers."
Deputy mayor for education and childcare Joanne McCartney added: "The importance of investment in a child's early years cannot be overstated.
"We know that a child's experiences in their early years lays the foundation for future success and happiness, but sadly our capital still faces significant inequalities.
"We're determined to give children the best start in life which is why we're launching these new programmes to help more families get access to the good-quality education their youngsters deserve. "