The Greens are insisting the Federal Government allocate at least $1 billion in this year's budget to meet a commitment on taxpayer-funded dental care.

The Greens have proposed introducing a Medicare-style dental scheme, which could cost about $5.5 billion, and a report on the feasibility of the plan is due from the National Advisory Council on Dental Health this week.

The Opposition thinks the Government is gearing up to scrap the dental deal with the Greens, after Prime Minister Julia Gillard said honouring the commitment needed to be weighed up in the budget process.

Greens health spokesman Richard Di Natale says he is optimistic, but wants significant start-up funds.

"There are existing schemes that can be used, but we think that unless you're talking about a scale of investment in the order of $1 billion or more that you're not going to make the necessary inroads in this year's budget that we need to make," he said.

"We do have an agreement with the Government that there needs to be significant investment.

"I'm optimistic that they will follow through with the recommendations of that report which I'm sure will recommend a significant investment in dental health over the coming years."

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Eyebrows were raised yesterday when Ms Gillard responded to a question about Labor's dental deal with the Greens.

Greens MP Adam Bandt asked Ms Gillard whether she would honour her commitment to the Greens.

In answering, the Prime Minister detailed spending commitments the Government had made to date, and then added: "But as we weigh what we can do in the budget process, we will of course make the appropriate fiscal decisions for the nation."