News Corp is reporting the government is facing a $9 billion black hole because it has shelved its plans to index future family and pension payments, which are being blocked by Labor, the Greens and the Palmer United Party.

But Mr Hockey on Sunday appeared to be still clinging to hope that he could strike a deal with enough senators, as seen with previously contested measures such as the mining tax and changes to financial governance laws which were passed with the support of PUP senators.

"No, don't believe everything you read," he told reporters at the G20 Finance Ministers meeting in Cairns on Sunday.

"I've seen lots of speculation about what we were going to do including from participants who said one thing to the media one day and on the very same day did something opposite to that," the Treasurer said.   But Mr Hockey refused to confirm or deny whether the government had struck a deal with Labor on means-testing family benefits for families earning more than $100,000 a year. "I'm not going to speculate," he said before ending his media conference.

The opposition's spokeswoman on families, Jenny Macklin, says the report, if true, constitutes a "humiliating backdown" for the government.

"I hope that the government is finally listening and will now scrap these unfair changes that will be so harsh on so many Australians," she told reporters in Melbourne.

"Labor has fought very hard against these changes and we've stood with pensioners and with families, with young people to stop these harsh cuts going through the Senate."