The Department of Health is to spell out to primary care trusts their duty to improve maternity services.
Its operating framework, expected next week, will "go further" on maternity than previous years.
This follows concern that additional funding is not being passed on to trusts, threatening delivery of the government's high profile commitments to better safety and choice.
A DH spokesman said: "In the operating framework for 2008-09, maternity services are an area where PCTs are expected to take particular action to improve access as part of the wider Maternity Matters strategy to deliver safe, high quality care.
"We plan again to underline the importance of maternity services in next year's operating framework.
"To emphasise this priority, we will go further than last year and intend to include a section setting out the requirements from Maternity Matters."
The 2007 strategy included commitments to quality, safety and "choice guarantees" to be met by the end of 2009.
Following a highly critical Healthcare Commission review in January, health secretary Alan Johnson identified£330m extra funding over three years to support delivery of the plan.
In addition to stressing PCTs' role, DH finance, performance and operations director general David Flory has reminded strategic health authorities of the need to closely monitor trusts rated poorly by the regulator.
A third of the£330m sum was included in PCT allocations for 2008-09, but providers and staff have complained they have not seen extra investment.
NHS London chief nurse Trish Morris-Thompson said stringent regional-level management was needed to ensure money was being spent and poor trusts were improving.
PCTs initially had difficulty "unravelling" the money from overall allocations, she said. A maternity services improvement board set up by the SHA had "helped them prioritise it".
It has also secured a commitment to further investment by the PCTs and is examining where funds are going "down to the minutiae and pennies".
She added: "We are performance managing the PCTs' commitment to investment and the providers in tandem."
Royal College of Midwives deputy general secretary Louise Silverton told HSJ: "We welcome the fact that maternity services are still seen as a priority and that PCTs are being asked to examine their services and make sure that they can provide a consistent level of service across England.
"We will be monitoring the delivery of these improvements in services and will be looking to see if the promised recruitment of additional midwives will match official projections."