Earlier this week, federal Treasurer Scott Morrison announced support for a compromised 15pc rate that was expected to pass this week during the final sitting week of 2016.

However, fears are now held that the tax will revert to 32.5pc on January 1, if the parliament is unable to resolve the matter this week.

The Senate’s unexpected backflip came after key crossbench Senators voted for an amendment moved by Labor and supported by the Greens to revert to the 10.5pc rate.

Victorian Senator Derryn Hinch did an unexpected backflip after earlier indicating this week that he backed the 15pc compromise rate announced by the Treasurer.

WA One Nation Senator Rod Culleton also parted ranks with his party saying he supported the 10.5pc rate as it was a better offer for farmers.

Despite criticism from Shadow Agriculture Minister Joel Fitzgibbon for being unrepresentative of farmers with their position on the backpacker tax issue, the National Farmers Federation stood its ground on a 15pc rate. 

NFF CEO Tony Mahar said his group believed that rate was fair, internationally competitive and recognised the unique nature of seasonal work.

“We don’t believe that backpackers should pay less tax than those on the Seasonal Worker Program,” he said.

“Our members will not be bullied on this issue and today’s antics in the Senate show contempt for farmers and growers in desperate need of a resolution.

“Enough is enough.

“We need this issue put to bed, once and for all.”

It’s understood the legislation will now return to the Lower House where it will be restored to 15pc and will then need to be returned to the Senate again.