Twyford's office said in a statement: "The changes to the Employment Relations Act require employers and employees to reach agreement on rest and meal breaks together. If agreement can't be reached rest breaks are to be taken in the middle of a work period."
He said the new rule gave flexibility to bus operators when scheduling rest breaks for drivers.
"This regulatory intervention is intended only as an interim solution while operators adjust their schedules to implement the changes."
First Union transport secretary Jared Abbott welcomed the memorandum of understanding - the deal aimed at implementing the changes for bus drivers provided for by the Act and the new land transport rule.
"It's the best that we could do that wasn't going to disadvantage drivers and wasn't going to severely disrupt the public."
He said that without the new rule 25 to 30 per cent of bus services would have been cancelled.
The rule allowed the Act to be overridden so that instead of having to take a break in the middle of a four-hour work period, bus drivers could have them at any time during the period. It might be close to the start for some, or the end for others. Some might technically start their shift - but not start working - 10 minutes earlier.
Council of Trade Unions president Richard Wagstaff said the agreement provided certainty while a permanent arrangement could be found which met the needs of bus users, drivers and management.
An Auckland Transport spokesman said some bus services would still be affected from next Monday but he couldn't say how many or which ones.
"We are still working through the figures. They will be off-peak services mainly. We will know the figure tomorrow."