A statement from the bus company added that the new timetable would be the "least disruptive" solution, and that it was now on the lookout for new drivers to urgently fill positions.
The metro travel news Twitter page had tweeted warnings to travellers in the region that buses around Dewsbury, Leeds and Wakefield would be affected as Arriva Yorkshire would be running a "scaled back" Saturday service.
Responding to this, Arriva Yorkshire tweeted: " Hi, We’re really sorry if we have let you down, we are suffering with the nationwide driver shortage."
It then linked to a lenghtier statement on its website, which said: "Bus companies across West Yorkshire have suffered from the UK-wide driver shortage over recent months, which has resulted in some last-minute cancellations.
"Buses not turning up because of last-minute cancellations goes completely against our service standards and what passengers rightly expect from us. We don’t want to let you down, and we’re sorry if we have done recently.
"We know the scaled-back timetable we’re introducing isn’t a perfect solution, but we’ve worked hard to ensure critical routes continue to be served, while less-used routes are served with less frequency. We feel this is the least disruptive option available to us.
"These changes should mean we have enough drivers to operate the published timetable and to minimise disruption, whilst we work behind the scenes to recruit new drivers to help us restore our services.
"We’d like to take this opportunity to thank our existing drivers, who continue to work extremely hard to run the level of service we do today. Their dedication is exemplary, and we’d like to thank them for their continued efforts."
The company also said it was recruiting drivers, and encouraged all readers who "know a friend or relative" who would be interested to apply at arrivabusjobs.co.uk.
Arriva runs 10 bus routes in Leeds, including the 110 to Hall Green, the 163/166 to Castleford, the 200/201 to Heckmondwike and the 202/203 to Huddersfield.
Arriva workers based in West Yorkshrie, including bus drivers and engineers, have been balloted for industrial action by the Unite union.
Unite said many of the bus drivers were struggling to make ends meet because of the cost-of-living crisis.
The ballot will close on May 23, so strikes could begin in early June if there is a yes vote.
For information on how your services could be affected, click here.