The 90-acre (36-hectare) garden will be formally opened by the Aga Khan, whose Trust for Culture has helped recreate the classical garden and restore its crumbling 16th-century monuments.
Some of the ancient tombs it contains were close to ruin before conservation efforts began around a decade ago, but have now been given UNESCO World Heritage status.
The park is a part of the historic complex that surrounds the Humayan's Tomb, the recently restored grave of a Mughal emperor that is widely seen as the inspiration for the Taj Mahal.
The Mughal dynasty ruled most of northern India from the early 16th to the mid-18th century and were famed for their architectural splendours.
Known as the Sunder Nursery, it was used in the early 20th century to propagate trees and flowers for the grand new city built when the British rulers moved the capital to Delhi from Kolkata. It remained in use as a government nursery, but the gardens themselves had become subsumed by jungle.
When the Aga Khan Trust for Culture first opened offices, they had to contend with cobras nesting in the half-ruined buildings, said general manager Luis Monral.
Now it combines lakes and pristine tree-studded lawns with Mughal-inspired formal gardens featuring marble fountains and geometric beds of brightly coloured poppies, marigolds and pansies.
Project director Ratish Nanda said he hoped the Sunder Nursery would become a green lung for the city and could eventually rival New York's Central Park.
"The idea would be eventually to create the largest park in Asia, linking the Sunder Nursery with the Humayan's Tomb complex and the Delhi Zoo," he said.
A Mughal-era Caravanserai that once catered to travellers on the Grand Trunk Road, which ran all the way from Chittagong on the Bangladesh coast to Kabul, abuts the site and could also one day be part of the park, he said.
New Delhi already has large amounts of green space but much of it is off-limits to the public - such as an exclusive golf course that takes up swathes of the city centre.