The wage row between the 900 drivers and their employer NZ Bus has kept most Auckland buses off the road since last Thursday.
The union issued a work-to-rule notice but the company said that was strike action and locked the drivers out of their depots.
Travellers had coped by switching to trains, buses provided by other companies, car pooled or brought their own cars.
But today with pupils returning after the school holidays, many of the buses used for public services last week were switched back to school routes.
An offer by the drivers to drive pupils for no pay was rejected by the company as "at best misguided and is at worst mischievous".
Pay talks at the weekend failed to resolve the claim by drivers.
Frustrated passengers have been told to go to the Auckland Regional Transport Authority (ARTA) website maxx.co.nz for alternatives.
ARTA spokeswoman Sharon Hunter said it had scraped together a skeleton bus service and the trains into the city were packed.
She said the daily subsidy of $160,000 paid to NZ Bus had been suspended while the buses were not running.
NZ Bus provides the bulk of public transport into and out of Auckland and around the city during the day but other operators, including Ritchies, Howick and Eastern, were expected to operate as normal.
Most of the alternative services were insisting on cash rather than pre-paid tickets.
Some passengers said last week the alternative services offered a better ride on more comfortable buses, with music and a friendly atmosphere.
Bus passengers should be patient, Ms Hunter said.
The industrial row has been going for five months but reached a head last week.
Union spokesman Karl Andersen said they could not understand why NZ Bus turned down a "bona fide offer" to drive the students at no charge.
He said the work to rule notice would have meant minimum, disruption and would not have stopped buses taking children to school. That was caused by the company lockout of its staff.
NZ Bus's general manager of operations, Zane Fulljames, said the union offer was a "media stunt" and "designed to be inflammatory".
