Birmingham City Council has been accused of trying to play down consultation over its plans for 6,000 homes and a major factory on Sutton Coldfield's green belt.
The final round of public consultation over the council's Development Plan was launched this month - at a time when many are on holiday and few public meetings are held.
Plans to build on land east of Walmley have proved highly controversial but were seemingly endorsed by government planning inspector Roger Clews who agreed that Birmingham should provide sites for 51,000 homes over the next 20 years - including the 6,000 on the green belt.
Sutton Coldfield MP Andrew Mitchell said consultation over such a contentious plan should not be launched in August.
"I welcome this eight-week consultation but what is of utmost concern to me is the timing," he said.
"I wrote to the city council explaining that planning policy since 2012 is very clear on its intent to allow people and communities to be able to fully participate in the planning process.
"Yet, our city council is still proceeding with a summer consultation where many of my constituents will be on holiday. It is therefore questionable whether the council is allowing my constituents time to fully participate in this consultation."
The consultation is strictly confined to elements of the plan modified by the planning inspector and the closing date for comments is October 12.
The council has organised four consultation events in Sutton Coldfield during September.
While the inspector has backed the use of the green belt sites at Langley for housing and Peddimore and Walmley for a large-scale factory, he resisted pressure from house builders and land owners to release more green belt land near Four Oaks.
Campaign group Project Fields believes the inspector could be persuaded to reconsider the sites or at least place a moratorium on development until a significant amount of Birmingham's available brownfield land is developed.
Campaigner Suzanne Webb said: "Everyone must use this opportunity to comment.
"You don't have to understand the technical detail of the consultation, just write why you know that building a 6,000 urban extension and employment site, the size of a JLR site, is not the right strategic decision.
"The city council needs to do more work to look for more reasonable brownfield alternatives before they erode what little open space Birmingham has."
All comments will be considered by the inspector who will then make a final decision on whether there is a strong case to release green belt.
Coun Ewan MacKey (Con Sutton Trinity) said: "The scale and size of this development will impact everyone in Sutton Coldfield and the surrounding area.
"It is important therefore everyone makes their comments known to the inspector about the negative impact this development will have.
"They should remind the inspector that all brownfield options should be explored first whether within or outside our city's boundaries."
A Birmingham City Council spokesman insisted it wanted residents to view the plans and have their say at four public events or via the council website.
He said: "Now that we have received feedback from the Planning Inspectorate on the Birmingham Development Plan, it is important that we move forward with this second round of consultation."
* A comment form can be found at www.birmingham.gov.uk.
Planning officers will also hold consultations at:
- Walmley Library: September 9, 10am - 1pm and 2pm - 5pm
- Sutton Coldfield Library: September 12, 10am - 2pm
- Walmley Library: September 19, 10am - 2pm
- Sutton Coldfield Library: September 22, 10am - 5pm