Extra train drivers may have to be used to reduce turnaround times at Newmarket's new $35 million station, the Auckland Regional Transport Authority has acknowledged.

The authority disclosed last night that it was considering asking its rail operator, Veolia, to post drivers at each end of western line trains at peak times to reduce delays which have become apparent since the station was added to its network on Monday.

Drivers now have to walk or even run from the front to the rear of their trains at Newmarket, before reversing direction through the adjacent junction of the western and southern lines.

That meant four trains observed by the Herald yesterday spent anything from one minute and 45 seconds to three and a half minutes at Newmarket, depending on how many carriages they were pulling.

The longest wait at the station was for passengers on a locomotive-hauled SA train, as they watched the driver walk 96 metres from one end to the other before pulling out of the station.

The train took five minutes, 10 seconds to get through Newmarket junction, which is just to the north.

Transport authority communications manager Sharon Hunter said her organisation had recorded times of between 60 and 94 seconds for drivers to change ends for western line trains but was considering measures to cut the delays.

"The option of employing relay drivers is already being considered for introduction when 10-minute peak frequencies are introduced across all lines," she said.

"If requirement dictates, then this introduction date will be reviewed."

Auckland transport consultant Stephen Greenfield said relay drivers would incur extra costs and add inefficiencies to a system which should have had a direct service between Britomart and the western line retained without trains having to over-shoot the railway junction.

Although the triangular junction includes tracks linking Britomart directly with the western line, the demolition of the temporary Kingdon St station over Christmas has reduced their usefulness for passenger trains.

Mr Greenfield says removal of the Kingdon St option will lengthen journeys to and from Britomart for western line passengers by at least three minutes.

That would mean more than 400 hours by the 8000 or so passengers who use the line each day.

"They are stuck with a lemon, no matter how much they flossie it up - it will never be a properly functioning system while the western line has to divert into the new station," he said.

"It will always take extra time - it builds dysfunction and extra costs into the whole network."

He described an earlier claim by Ms Hunter that the new station would add only about 30 seconds to western line journeys as "outrageously specious" and called for the Kingdon St facility to be reinstated "to restore some integrity to the network".

Ms Hunter defended her claim as an estimated difference in journey times between Britomart and the Boston Rd station in Mt Eden, comparing existing operations and those before Christmas when trains stopped at Kingdon St.

She said the extra time spent at Newmarket was compensated for by the fact that there were no longer delays caused by construction activity, and by an improved time from the new to Boston Rd because of not having to stop on a gradient at Kingdon St.

The completion of track duplication on the western line and an upgrade of the Quay Park junction of the southern and eastern lines on the Auckland waterfront would further improve running times, she said.

Campaign for Better Transport spokesman Jon Reeves shared Mr Greenfield's concerns, which he believed would be compounded when longer six-car trains were added to the network.