Sydney trainers will have more flexibility over morning trackwork with the Australian Turf Club to trial later finishing times.

After consultation with trainers at Randwick, Rosehill and Warwick Farm, the ATC has decided to extend trackwork finishing times to 9am at Rosehill and Randwick, and 9.30am at Warwick Farm from July 1.

The majority of trainers at all venues indicated that they did not support later starting times for trackwork sessions at this stage.

ATC executive general manager of racing services James Heddo said the changes were in response to recent debate about the prospect of losing foreign workers under changes to the federal government's 457 visa system.

"Whilst there isn't widespread support for a later start, this trial acknowledges that the needs of trainers and their staff is changing and will still give trainers the option of allowing their staff and stables to start later and finish later in the morning if they desire," Heddo said.

"We will continue to monitor the trial and work with our trainers to ensure the optimum outcome for all participants.''