Up to 20 metres could be shaved off historic Ashfield Park under the current WestConnex plan, according to executives from the motorway project who appeared before a crowd of more than 400 angry residents affected by the multi-billion dollar plan.

Residents who gathered for the community meeting at the Ashfield Civic Centre on Monday night jeered three representatives from the Westconnex Delivery Authority about the lack of detail on the plan.

A preliminary plan showing WestConnex slicing a section from Ashfield Park.

Director of transport planning Natalie Camilleri, infrastructure development manager John Betts and communication manager Ed Scully were unable to answer questions regarding access ramps to the toll road, the location of portals and emission stacks and the exact number of properties that would be affected by the construction.

However, they did confirm that between 10 metres and 20 metres will be cut from the length of the National Trust-registered Ashfield Park to make a cutting two lanes wide for a seven-metre portal.