Independent senator Jacqui Lambie has delivered a searing blow to the Coalition, questioning their ability to function as a "credible opposition".

With the five-week election campaign passing the crucial halfway point, the opposition has continued to languish in the polls, with Sunday's Newspoll revealing its primary vote falling to 35 per cent, a figure even lower than its 2022 election loss.

Labor also continued to lead Peter Dutton's Coalition 52-48.

Speaking to the ABC, the Tasmanian senator questioned why they had waited until week three of the campaign to roll out their major policies such as the on-off tax cut of $1200 for low and middle class income earners who earn up to $144,000 a year.

2021 Census figures suggest the median gross weekly equivalised household income of Indigenous adults (aged 18 and over) was $825, with the mean gross weekly equivalised household income for Indigenous adults being $1,005.

Peter Dutton also used his Sunday campaign launch to announce tax-deductible mortgages which would allow eligible borrowers to deduct their interest payments on the first $650,000 of their loan amount.

The Coalition has also continued to face questions over their nuclear policy, including how much waste would be generated, and how the party would bypass community dissent.

"What bothers me is the Liberal Party should have got this all done 12 months ago. They have been in opposition for three years, they don't look like they're in opposition at all. they're really struggling with that," she said.

"They should have had costings, they had plenty of time to get it ready and looking like a real smart outfit.

"They failed to do the work to make them look like a credible opposition."

The Palawa woman also said given the school holidays, both party leaders would likely struggle to achieve cut through over the next two weeks, with people also switching off from the news due to the Easter and Anzac Day long weekends.

"I don't know how they're going to go in the next two weeks campaigning. How difficult is it, when no-one wants to see your face, let's be honest," she said.

"The last thing you want is some bloke in front of you with his bloody jacket on."

Liam Beatty, Sarah Keoghan, Jessica Wang and Blair Jackson - NCA NewsWire