Treasurer Scott Morrison has defended his ability to make the Government's economic pitch to voters, saying he is not being sidelined by the Prime Minister.

There are concerns inside the Coalition that Mr Morrison's efforts may not be enough to sell the Government's economic policy in the lead-up to the May budget.

Government sources said Malcolm Turnbull planned to make a series of keynote speeches over coming weeks to try to form a stronger economic message, but Mr Morrison said that did not mean he was being sidelined.

"The Prime Minster is always the chief economic spokesperson for the Government, always has been, always should be," he told the ABC.

"The Prime Minister and I work together as a team on these things, we work on budgets together."

Opposition Leader Bill Shorten has leapt on the reports, accusing the Prime Minister's supporters of "publicly humiliating the Treasurer".

"If the Prime Minister doesn't have confidence in the Treasurer, he should remove him," he said.

"While these two characters are fighting each other and undermining each other, no-one's looking after the Australian people.

The ABC also understands there will be a Cabinet reshuffle after the budget.

Attorney-General George Brandis will move on by June, if not to London as High Commissioner then to another prominent position.

Senator Brandis will likely be replaced by Social Services Minister Christian Porter or Employment Minister Michaelia Cash, and his position as Government Leader in the Senate would go to Finance Minister Mathias Cormann.