PM to blame if credit rating slips: Labor

Prime Minister Malcolm Turnbull and Treasurer Scott Morrison should be held responsible if Australia's credit rating slips, Labor claims.

Shadow Treasurer Chris Bowen says Labor had built up the country's credit rating but delegated the task of protecting it to the coalition.

"If the triple-A rating were to be lost under Mr Turnbull and Mr Morrison's watch, they would be responsible," Mr Bowen told reporters in Sydney.

The treasurer said two of three ratings agencies had confirmed Australia's triple-A rating in the past few weeks.

Fitch Ratings had warned against increasing government debt to GDP radio, Mr Morrison's office said.

Mr Morrison blames Labor's irresponsible spending for Australia's structural budget problem, saying Labor's "tax and spend" policies would increase the nation's debt challenge.

"The Turnbull government's responsible budget management will help protect our triple-A credit rating," a spokeswoman for Mr Morrison told AAP.