- Wandsworth's officers have decided there are no "very special circumstances" that would outweigh the harm caused.
- The extra courts would allow Wimbledon qualifying to take place on-site - in line with the other three Grand Slams.
The All England Club's proposal to build 39 new tennis courts, including an 8,000-seater show court, has suffered a setback.
Officers at Wandsworth Council have recommended councillors refuse planning permission as the development on Wimbledon Park would be "inappropriate" and cause "substantial harm" to the land.
Merton Council, which is responsible for all but the most northerly part of the land, voted in favour of the scheme last month.
Its officers accepted the proposals would result in "physical harm" to Metropolitan Open Land, but concluded "very special circumstances" meant "substantial public benefits would outweigh [the] harm".
Wandsworth's officers have decided there are no "very special circumstances" that would outweigh the harm caused.
"The proposed development would result in the net loss of open space/green infrastructure, with no replacement provision provided," the report concluded.
The planning committee will vote on the matter next Tuesday, after which the Mayor of London, Sadiq Khan, will have two weeks to deliver his verdict.
The extra courts would allow Wimbledon qualifying to take place on-site - in line with the other three Grand Slams.
The All England Club has also promised to create a new 23-acre public park in the spirit of the original design of landscape architect Capability Brown. At least seven of the grass courts would be made available to the local community for the summer weeks which follow Wimbledon.
But local opposition has been strong, and members of the Save Wimbledon Park organisation protested outside the chamber when Merton Council met to vote on the issue.
They highlight the issues of the environmental impact and the loss of trees and open spaces.
A petition has attracted more than 14,000 signatures and both local MPs - Conservative Stephen Hammond and Labour's Fleur Anderson - are opposed.
Anderson says she is "delighted" at Wandsworth's recommendation, which she described as "a very positive step in the right direction".
The All England Club said: "We are surprised that planning officers at the London Borough of Wandsworth have recommended refusal of the AELTC Wimbledon Park Project, particularly after the London Borough of Merton resolved to approve the application following extensive analysis and debate both in their officers' report and at the Planning Committee.
"We regret that Wandsworth's officers have taken a different view but it is for Councillors on the Planning Applications Committee to make their own considered decision at the meeting on 21 November.
"We firmly believe the AELTC Wimbledon Park Project will deliver substantial social, economic and environmental benefits, including 23 acres of newly accessible green space, alongside hundreds of jobs and tens of millions of pounds in economic benefits for our neighbours in Wandsworth, Merton and across London."