The Abbott government's plan to cut paid parental leave entitlements to about 80,000 new mums is struggling to find support in the Senate, with more than half of the crossbench undecided or holding serious concerns about the proposal.

As the first week of its budget sell drew to a close, the government also struggled to keep its paid parental leave message on track - with confusion over whether the Coalition would have to make changes to its budget policy.

With Labor and the Greens fiercely opposed to the $1 billion paid parental leave cut, the government needs six of the eight crossbenchers to pass its new parental leave bill - due before Parliament in the spring sitting later this year.

But so far only Liberal Democrat Senator David Leyonhjelm​ and Family First's Bob Day have indicated they will support the new bill. Victorian independent John Madigan is still considering his position, as is Motoring Enthusiast senator Ricky Muir.

In a sign of complicated negotiations to come, Tasmanian independent Jacqui Lambie said there needed to be an "adequate" safety net for those who had no employer scheme. She suggested all women have access to a government-backed $25,000 payment over six months if they didn't have a more generous employer scheme.

Currently all women get 18 weeks at the minimum wage, which is $11, 500. But the Coalition wants to stop women accessing both the government scheme and their employer's one, if one exists.

A spokesman for Senator Lambie said an increased government scheme could be funded by pulling Australian troops out of Iraq or further overseas aid cuts to countries such as Indonesia, Pakistan and Vietnam, which have significant militaries.

Independent Nick Xenophon is also flagging an issue for negotiations. The South Australian has said "at the very least" there needs to be a way of transitioning from the existing scheme, because some women will have made plans based on workplace agreements that still have a couple of years left to run.

Independent Glenn Lazarus and Palmer United Senator Dio Wang did not responded to inquiries before deadline, although PUP leader Clive Palmer said earlier this week the PPL policy needed to be "further investigated".

The uncertainty on the crossbench came amid confusion about the government's new policy on Friday.

During a press conference in Sydney's west Prime Minister Tony Abbott briefly had reporters thinking that the government would scale back the new plan to just affect public servants. His office quickly clarified that the Prime Minister misheard the question and that there was no change in the policy.

Treasurer Joe Hockey also described businesses who rebadged their PPL schemes so women could access both a work and government payment as scammers.

"If they ... try and scam the government and scam taxpayers, well, I mean that reflects on them as much as anything," he told ABC Radio in Melbourne.

Mr Hockey added that the taxpayer's scheme was meant to be a "safety net" for when businesses could not provide a payment and that the government would "have a look at" businesses trying to get around the new policy.

The public sector also hit back at the Coalition's argument that it was unfair for public sector employees to access both a government and workplace scheme, because both were paid for by the taxpayer.

"Public servants are actually citizens and taxpayers," Community and Public Sector Union national secretary Nadine Flood said.

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