The Federal Government is preparing to drop or radically rework one of its most contentious budget policies – the $7 GP co-payment.

With only five full sitting days left in the parliamentary year, Prime Minister Tony Abbott was keen to start 2015 on the front foot.

On Tuesday, he told Coalition MPs and senators there were one or two “barnacles” on the Government but they would be knocked off by Christmas.

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One of those “barnacles” was the $7 GP co-payment, which did not have sufficient support to pass the Senate.

The Government is yet to even introduce legislation to enact the measures in the Lower House and is now unlikely to do so.

Sources had told the ABC the Coalition was “willing to go back to the drawing board”.

The Government was also expected to make further changes to its $5.5 billion paid parental leave scheme, a signature policy for Mr Abbott.

The policy would pay new mothers their full salary for six months.

Mr Abbott had already watered down the scheme, lowering the maximum possible payment from $75,000 to $50,000.

Further changes were now in the works.

Government sources denied the scheme was one of the “barnacles” mentioned, but they had foreshadowed “further refinement”.

Budget is like re-marketing the Hindenburg: Shorten

In an address to the National Press Club, Labor leader Bill Shorten said Australians knew the budget was unfair.

“Every time they scrape off a barnacle, they just reveal another hole in the hull,” he said.

“A new set of talking points won’t fix this budget – it’s like raising the Titanic or re-marketing the Hindenburg, and that’s really hard.”

In Question Time, Mr Shorten asked which barnacle the Prime Minister would be scraping off: “His disaster of a Defence Minister or his disaster of a GP tax?”

But Mr Abbott turned the phrase against the Labor leader, labelling him “Barnacle Bill” after the character from the Australian children’s classic The Magic Pudding.

“They were incompetent in government, they are wreckers in Opposition, the barnacle that most needs to be gotten rid of is Barnacle Bill sitting opposite,” Mr Abbott said.

The Prime Minister has also been forced to defend his Defence Minister, David Johnston, over an extraordinary attack on Tuesday on the Government’s ship-building company, which Senator Johnston accused of not being able to “build a canoe”.

Earlier in his speech to the Press Club, Mr Shorten announced Labor would join the multi-billion-dollar Asian Infrastructure Investment Bank if it won government.

The Beijing-based fund has been established to pay for major infrastructure projects in the region and is regarded as a rival to the World Bank and the International Monetary Fund.

Cabinet’s National Security Committee decided not to join the fund amid concerns about its transparency and governance arrangements.

But Mr Shorten said the Government had missed an “unparalleled economic opportunity for Australia”.

“If Labor was in government, we would have got the details right, and we would have signed up,” he said.

“When we are in government, we will get the details right, and we will sign up.”

-ABC