Auckland Council transport chairman Mike Lee believes KiwiRail should consider delaying long-distance train departures from Britomart to free up a slot for a Waikato commuter service.
That follows advice to his committee that Britomart will reach capacity in February, when it will have to cope with extra trains from the new Manukau branch line and an increase in services on the western line to a turnaround every 10 minutes.
A working party on which Mr Lee sits has accepted a likelihood of having to drop commuters off at the recently reopened Strand station below Parnell because of the Britomart bottleneck.
The morning Waikato train would end its run at Newmarket, before doubling back to Britomart to pick up passengers for a return journey.
Britomart could also be used to take off-peak passengers to central Auckland in a second daily service, but early-morning commuters would have to catch a bus from The Strand.