Transport Secretary Patrick McLoughlin said the 1.9km bored tunnel already proposed to take the line under the airport could be extended by 1km.
This would ensure it does not interfere with plans for the nearby Roxhill strategic rail freight interchange depot.
The Department for Transport will consult on the route later in the year as part of its public consultation on phase two before a firm commitment is made.
In the meantime, the developer will progress its plans for the proposed depot.
Kate Bedson, senior development director at Roxhill, said: “Our proposals for a new SRFI with 6m sq ft of associated warehousing have the potential to create 7,000 jobs, providing a boost to the economy in the region.
“Since the announcement, through our MP and local authority, we have enjoyed an early and positive dialogue with DfT and HS2 Ltd and are very pleased with the decision to amend the proposed route.
“This now allows us to consult with the public and other bodies on our plans before submitting our application at the end of the year.
Transport Secretary, Patrick McLoughlin, said: “These changes have the potential to deliver huge economic benefits for the East Midlands on top of the already considerable opportunities HS2 will bring the region.
“We will continue to work with stakeholders, to identify critical issues such as Roxhill and propose revisions to the scheme where possible.”