Christchurch bus passengers are being warned to plan ahead next Wednesday after several Metro routes were flagged for disruption due to a driver union meeting.

Services on four routes will be affected between 9am and 2pm on Wednesday 22 April, with some trips potentially ending early at the city bus interchange as drivers prepare to attend the meeting.

The affected routes are Route 3 Airport or Sheffield Crescent/Sumner, Route 8 Port to Port, Route 140 Russley/Mt Pleasant, and Route 155 Eastgate/Lyttelton Shopper Service.

Ritchies, the operator whose drivers are attending the meeting, said it had worked to ensure its remaining routes would be unaffected.

School services will not be disrupted.

Under their collective agreement, bus drivers are entitled to attend up to two union meetings per year, and Wednesday’s meeting is one of those.

Metro said affected trips would be removed from live information on go.metro.co.nz and at bus stops, and that services were expected to be running as normal by 2pm.

Passengers travelling on the affected routes are encouraged to check the Metro website before heading out.