Up to 70 per cent of bus services across Auckland will be disrupted on Friday when 900 bus drivers hold a stop work meeting to decide on a new pay offer.
Mediation was held between NZ Bus and Auckland Tramways and First unions on Monday with the company offering a 6.6 per cent pay increase over 27 months.
The groups have been in negotiations since June.
First Union spokesman Karl Anderson told NZ Newswire the unions would not be recommending its members accept the offer when they vote at a meeting from 1-4pm on Friday.
The drivers had originally sought rises totalling between 7.2 per cent and 8.3 per cent over two years, and for it to take effect from the end of the present collective.
Mr Anderson would not say whether the unions are now asking for less but says the company and the unions are "not that far apart".
He says pay rises between 7.2 per cent and 8.3 per cent had been agreed for unionised workers from all other major Auckland bus companies this year.
Drivers could take industrial action if they decide not to accept the company's pay offer, Mr Anderson said.
NZ Bus chief operating officer Shane McMahon told NZ Newswire the unions stance was disappointing.
Details about the extent of disruptions to bus services would be revealed on Tuesday, but it was likely to be extensive, he said.
The company, a subsidiary of Infratil, runs about 70 per cent of Auckland's buses, including the North Star, Go West, Metrolink, City Link, Outer Link and Waka Pacific buses.
NZ Bus employs about 1000 bus drivers.