Shadow treasurer Chris Bowen is insisting he knew the tax-free threshold rate but chose not to give the answer during an embarrassing live TV interview because he says the answer was irrelevant.

Labor tripled the tax-free threshold in 2012 from $6000 to $18,200 as part of its carbon tax compensation plan.

Shadow treasurer Chris Bowen. Credit:Andy Zakeli

But when asked to name the figure on Sky television by host Alan Jones in an interview that ranged from questions on superannuation rates and thresholds to the general tax-free threshold, Mr Bowen was unable to provide an answer.