The warning from the union representing Auckland's bus drivers came as there was already a rail strike under way in the city.

More strike action is looming in Auckland's already hobbled public transport sector — this time involving the city's bus drivers.

A union representing drivers threatened industrial action on Thursday, saying a new tendering system is putting their incomes in decline.

The warning came amid ongoing strike action by the Rail and Maritime Trade Union (RMTU), affecting some peak train services on Auckland's southern, western and eastern lines.

Commuters have experienced hour-long delays amid the start of universities' semester one this week.



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Bus Drivers First spokesperson Graham McKean said several disputes between bus drivers and their employers were looming, after drivers voted to go on strike at a number of major companies providing bus services in the city.

"The new tendering system has failed Auckland's public transport passengers," he said.

"Bus drivers' incomes are going down, and they are saying enough is enough."

The union had been campaigning for an end to the Public Transport Operating Model (PTOM), which favoured low-paying bus operators, McKean said.

Under the model Auckland Transport awarded public bus contracts to private providers offering the lowest fee.

"We want to avoid further disruption to Auckland's public transport passengers if we can, but this situation has been going on for months.

"Unless we start to see a real improvement from bus companies our members are left with little choice."

A spokesperson for Auckland Transport said as discussions were between bus operators and unions, it wasn't appropriate for AT to comment.

Meanwhile, RMTU organiser John Kerr said progress had been made at talks on Wednesday with train company Transdev, but the rail strike had not been lifted.



"We've got another meeting on Monday, and we're hoping that by the end of that well be in a position to lift the industrial action," Kerr said.