Amidst serious budget concerns from both Labor and Coalition lawmakers, Prime Minister Julia Gillard is likely to grant federal subsidies of around $1.4 billion each year that will finance higher pay for private childcare workers.

The fresh initiative is Ms Gillard's third wage boost plan following her earlier commitment of funding higher annual salaries for female workers and those in the aged care sector.

The earlier pledge, according to Fairfax, will cost the federal government $2 billion and $1.2 billion respectively.

Media reports have indicated that the prime minister will outline the specifics of her new deal with the labour group United Voice on Wednesday but her finance minister, Senator Penny Wong, branded the reports as bordering to speculations.

"I wouldn't be holding your breath for that speculation turning into an announcement today," Senator Wong was reported by The Australian as saying today.

The wage funding plan emerged as the Labor-led government faces questions on the manner it handles the federal finances, with some of the reservations on Treasurer Wayne Swan's budgeting priorities raised within the ruling party ranks.

Labor backbenchers expressed alarm that high-profile government expenditures were being inserted in a fiscal budget that has been programmed to deliver a surplus of at least $1.5 billion by 2013.

In order to support the financial course that Mr Swan has mapped out, the government should at least expand its tax base beyond the current level of 22.1 per cent of gross domestic product (GDP), Labor Senator Doug Cameron said on Tuesday.

More revenue sources, Senator Cameron added, would ensure that money will be flowing to finance the realisation of major programs that Ms Gillard had previously announced.

Among them are the national disability insurance scheme and the school funding reforms that will cost taxpayers billions each year once they are fully operational.

The government, according to Shadow Treasurer Joe Hockey, must rationalise its spending habit considering that in the current year alone it stands to deal with revenue shortfall of about $25 billion, no thanks to shrinking company tax receipts.

Mr Hockey called on his counterpart, Mr Swan, to strike out from the national budget planned multi-billion subsidies "for workers in the childcare sector who are not even employees of the commonwealth."

He noted too that even Labor members have expressed uneasiness in the way party policy makers were using the national purse.

"Their own MPs are in rebellion about their unfunded spending," Mr Hockey was quoted by the Australian Associated Press (AAP) as saying yesterday.

For his part, Opposition Leader Tony Abbott accused the government "of spending like a drunken sailor."

While he acknowledged that childcare workers deserve to take home higher pay, Mr Abbott assailed the Labor government for "raising expectations without the means to meet them."

"It is writing cheques against the future, which it expects someone else will have to cash," the Liberal leader was reported by Fairfax as saying on Wednesday.