Turnbull takes lead in housing budget plan

The prime minister's own department is taking the lead in a committee bringing together government departments to develop a new affordable housing policy ahead of the May budget.

A Senate inquiry was told an inter-departmental committee was being chaired by the prime minister's department, rather than Treasury which is responsible for housing supply issues and the Department of Social Services which oversees housing affordability and homelessness.

Treasury official Marty Robinson said work was being done ahead of the budget on the "social and affordable segments" of the housing markets.

Mr Robinson said the Department of Prime Minister and Cabinet had become involved because the work overlapped with the department's work on cities policy.

Malcolm Turnbull last week flagged expanding his "city deals", announced during last year's election campaign, to capital cities in a bid to make housing more affordable.

'What we are doing as we set up our city deals... is reach agreement so that as commonwealth funding is made available for road or rail or whatever that is then part of a deal and a commitment to deliver, for example, more dwelling approvals,' Mr Turnbull said.

City deals are planned for Townsville, Launceston and western Sydney.

Treasurer Scott Morrison was asked on Monday whether he had been sidelined from the budget, the centrepiece of which is expected to be the housing affordability plan.

Mr Morrison told Bloomberg TV the prime minister was the "chief economic spokesperson" and his job was to work closely with Mr Turnbull.