Stafford Hospital, which was renamed County Hospital, was at the centre of a Â£6m public inquiry into care failings.
Shadow health secretary Andy Burnham would not give an exact time scale, saying he didn't want to make promises that "can't be delivered".
Overnight closures at the hospital began in 2011.
Consultant-led maternity services were moved in January.
Mr Burnham said he wants to see a return of full maternity and accident and emergency services to Stafford.
On a visit to Stafford two weeks ago, Health Secretary Jeremy Hunt said if the Conservatives won the election, overnight services would be restored as soon as soon as it was "clinically safe" to do so.
Labour has said that within 100 days of winning it will commit "additional resources needed to fulfil Ed Miliband's long-term pledge to fund the hospital Stafford needs".
It's no wonder Andy Burnham wants to talk about the NHS - it's the top priority for voters and one of the few areas where polls show Labour are trusted more than the Tories.
In Stafford, where A&E's been closed overnight and maternity services downgraded since the inquiry into care standards, it's even more important. Paediatric inpatient beds are moving elsewhere later this month.
But although campaigners blame Labour for allowing the scandal to happen on their watch, the party believes it's got a real chance of overturning a Tory majority of more than 5,000 to win the Stafford seat back on Thursday.
The Liberal Democrats said last month that Westminster should not tell local areas how to run hospitals.
UKIP said both the Conservatives and Labour "have promised to wave a magic wand to restore Stafford Hospital to full service, when it was they who forced this situation in the first place."
The National Health Action Party, which is fielding a candidate in Stafford, has described both the Tory and Labour pledges to restore services as an election bribe.
Mid Staffordshire NHS Trust, which ran the hospital, went into administration in April 2013. The hospital was taken over by the newly-formed University Hospital of North Staffordshire NHS Trust.
A full list of candidates for the Stafford constituency can be found here.
Labour has promised to reintroduce a "full range of services" at Stafford's hospital if it wins the general election, but have not said by when.