The Department of Home Affairs has rebuffed the CPSU's alternative resolution to the pay stoush that has dogged the department for almost five years.
The Fair Work Commission held its final hearing on the matter on Tuesday, with the government's lawyer saying the proposal "should not be accepted".
The main public sector union
in its closing statement to a full bench of the Fair Work Commission on Monday, suggesting the commission could make a decision that would preserve terms and conditions within the agreement that covered staff under the then Department of Immigration and Citizenship, with an attached schedule that would preserve the terms and conditions that apply to staff within Australian Border Force that are covered under the previous Customs agreement.
The CPSU said the option could come into play if the commission did not accept either side's argument in full.
Paul O'Grady QC, acting for the government, told the full bench on Tuesday that the union's proposal would create more work in their decision making, rather than easing the burden.
"The CPSU is inviting you to abdicate your statutory responsibility to make a workplace determination," he said.
"It would be inappropriate for the full bench to be seduced by this proposal."
Mr O'Grady also attacked the proposal as "antithetical" to the CPSU's case, which has long argued that all staff in the department should have the same terms and conditions for the same work.
A key sticking point in the case has been the different terms and conditions that apply to workers from the former Customs department, before it merged with Immigration and became Australian Border Force in 2015. The unions have argued that Customs staff should not face losing their conditions or a pay freeze in the new deal.
The department has argued that if all staff were to be entitled to the terms and conditions put forward by the CPSU, it would cost $469 million more than its proposal.
While this is the last stretch of the tussle between the union and the government, it is not necessarily going to be over quickly. Fair Work Commission vice president Joseph Catanzariti said on Monday that when the Fair Work Commission is called to arbitrate on enterprise agreements it usually only considers three or four clauses, whereas in this case the whole agreement was before the commission.
Tuesday's hearing explored the possibility of releasing its determination in parts, with parties eager to hear an outcome on wage rises in the department before the federal budget on May 8.