NZ Bus tonight offered to lift its lockout of Auckland bus drivers so buses could resume first thing on Thursday morning. But it demands that by 1.30pm tomorrow the unions have to lift their work to rule (which the company calls strike notice).

The company also wants the union to agree to work with the employment relations authority facilitator James Wilson to reach a ratified settlement.

Mr Wilson is due to make a judgement in the dispute at 10am tomorrow.

NZ Bus' GM of operations, Zane Fulljames, said it was impossible for buses to resume tomorrow.

Since Friday, the company and the coalition of four unions that make up the Auckland Combined Unions have been in facilitation with the employment authority to resolve their five-month long pay dispute.

Mr Fulljames said the facilitator has outlined a basis on which he considers a settlement can be reached.

Earlier today, the Auckland Regional Transport Authority waved a stick at NZ Bus giving a 5pm deadline for the immediate resumption of contracted services saying the lockout has meant NZ Bus is in default of its service agreements.

The authority's head Fergus Gammie wrote: "Generally ARTA does not involve itself in employment disputes as this is a matter best dealt with by all the parties involved.

"However the NZ Bus lockout has now been in place for five days and this is having a significant impact on Auckland bus users."

The unions representing the bus drivers and cleaners who work for Metrolink, North Star, Go West, Waka Pacific, LINK and City Circuit bus services had threatened to work to rule last week and the company responded by locking out the workers.

The Auckland unions will meet with their members at 11am tomorrow to discuss developments.

NZ Bus said that because the drivers and cleaners will be at the meeting, " bus services can not resume tomorrow."