Scott Morrison has emerged as the Abbott government's chief salesman in the final week before its second budget is handed down, giving 16 interviews in seven days while Treasurer Joe Hockey has given just four.

Mr Morrison has carriage of the budget's families package and of the proposed pension changes, which will save $2.4 billion over two years and was revealed on Thursday.

He is already on track for a major win with the Greens and the welfare lobby signalling they could support changes to pension asset testing that would boost pensions for low and middle-income earners but take away the part-pension for wealthier people.

His media blitz stands in stark contrast to the low-key approach of Mr Hockey, who has given just four interviews in the past week.

Mr Hockey's political allies defended his low key approach on Thursday, pointing out he gave a similar number of interviews last year and that he has been locked away in the federal Treasury finalising a make-or-break second budget for the Abbott government.

They also said it was deliberate political strategy to give ministers licence to get out and explain measures contained in their portfolios. After the budget is handed down, one said, Mr Hockey will be "everywhere".

But the marked rise in the Social Services Minister's public presence came as fresh questions emerged on Thursday about Mr Hockey's future in the portfolio and amid suggestions Mr Morrison could replace him.

But Prime Minister Tony Abbott said that he had reassured Mr Hockey he will remain in the job until the next election, regardless of the reaction to next week's budget.

The comment came amid reports Liberal Party Whip Scott Buchholz, speaking on behalf of the backbench, had told Mr Abbott two weeks ago that if the budget was a failure then the Treasurer would have to go.

"I think some people just make things up," Mr Abbott said, adding that the budget was a "team effort".

Political insiders say the addition of Mr Morrison and Assistant Treasurer Josh Frydenberg to the expenditure review committee (ERC), as well as new secretaries in the departments of Prime Minister and Cabinet, Treasury and Finance has strengthened the ERC, which has been holding regular working dinners and meeting for three to six hours, two or three times a week.

Despite the Prime Minister's denial, Liberal MPs both in and outside of the cabinet confirmed the party room was increasingly nervous about Mr Hockey's ability to sell the second budget.

One cabinet minister expressed amazement at the leak against Mr Hockey, wondering: "Are they trying to turn Joe into a lame duck before he gets up to speak on budget night?"

"It's critical that people feel confident in the government's management of the economy and that's inextricably linked to the Treasurer. If you undermine the credibility of the messenger then the confidence in the message is also undermined."

The pensions overhaul proposed by Mr Morrison will mean 170,000 low to middle-income pensioners will be $30 a fortnight better off on average, though about 91,000 wealthier retirees will lose access to the part-pension and about 236,000 will see their payment decrease.

Last year's budget plan to index pensions to CPI, rather than average male weekly earnings - driving down the value of 4 million pensions over time - has been dumped.

The asset threshold for a retired couple, for example, would be reduced from $1.15 million to $823,000 for a retired couple, excluding the value of the family home.

Mr Morrison said the measure would save $2.4 billion over two years, would not say how much it would save over 10 years but conceded it would be less than the $23 billion over 10 years expected from pension indexation changes.

Cabinet met on Thursday to lock in key budget measures, while the ERC is due to meet again on Sunday and a final cabinet meeting will be held on Monday before the budget is handed down. The budget will squarely target the Liberal base by focusing on a small business tax cut, a jobs package and the families package.

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