Mr Gillard was responding to the Coalition's pledge on Thursday morning to support the rise.

But Opposition Leader Tony Abbott vowed that the levy raise would be removed if it wins the next election once the budget returns to ''strong surplus''.

After a phone hook-up with his leadership group on Thursday morning, Tony Abbott announced the opposition's support for the proposed 0.5 per cent increase in the levy, despite uncertainty about where the rest of the money will come from and who DisabilityCare will cover.

''This is not a day to be quibbling over something which is very, very important to the future of our country,'' Mr Abbott told reporters at Koroit, in Victoria's western district.

''The Coalition is prepared to consider supporting this because we want it to go ahead.

''We are not in the business of putting obstacles in the way of a very important reform, which belongs to all Australians and which should be the property of both sides of Parliament.''

VIDEO: Opposition Leader Tony Abbott gives conditional support to raising the Medicare levy to fund a national disability insurance scheme.

Pressed on whether this was a ''rock solid'' guarantee, Mr Abbott replied: ''No one should ever give this particular government a blank cheque. This government has a record of incompetence and untrustworthiness, but in  this particular subject I am prepared to take the Prime Minister at her word.''

Mr Abbott also wants the Government to spell out the scope of the scheme, asking: ''Are people with autism in or out? Is vision impairment in or out? Hearing impairment, in or out? Mobility assistance? To what extent is that covered?

''These are all very important questions which will really determine whether this is the breakthrough that it ought to be for people with disabilities.''

Mr Abbott said that the scheme was not to become fully operational for six years and the levy rise would raise only 40 per cent of the money that was needed.

''There are a lot of things that are yet to be clarified but the Coalition is prepared to work fully with other elements in the Parliament. We want this to become a reality – an affordable, sustainable, comprehensive reality for the people of Australia.''

Mr Abbott urged the Government to set up a bipartisan committee to oversee the implementation of the scheme. ''I think, if the Prime Minister is fair dinkum about wanting this to be above politics, that would be a very good way of demonstrating it,'' he said.

''The commitment I have made is that, if we do win the election in September or whenever it's held, that we will establish such a committee because this is too important for it to get lost amongst all the other things that the Parliament has to consider.''

He also vowed that a Coalition government would ''restore the budgetary position and over time that certainly will mean tax cuts''.

In a separate statement, Mr Abbott said in incoming Coalition government would resolve to ensure that the increase to the Medicare levy is a temporary increase and ''will be removed when the budget returns to strong surplus and the NDIS can be funded without it''.

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The statement said the Coalition believed:

All elements of the NDIS required for launch must be legislated in the current parliament and all the operational detail for the scheme made public.

The Disability Care Australia Fund to be established to hold levy proceeds should be legislated in the current parliament and be supervised by the Guardians of the Future Fund to prevent ''the raiding of this fund as occurred with the Higher Education Endowment Fund''.

The assessment tool to be used to determine participant eligibility should be released before the levy legislation being introduced to provide maximum transparency about scheme eligibility.

The government should release all elements of the bilateral agreements between the Commonwealth and each jurisdiction for launch sites and full roll-out.

Prime Minister Julia Gillard is yet to respond to Mr Abbott's comments.

She was in Tasmania this morning to announce her signed agreement, with Tasmania Premier Lara Giddings, for the roll out of the NDIS in that state by 2019.

In the deal, the Tasmanian government will contribute $232 million and the Commonwealth will give $245 million to the scheme.

The Prime Minister was asked in an ABC radio interview on Thursday morning whether she would take the NDIS legislation to the next sitting of parliament if Mr Abbott supported the levy.

''Yes we will,'' Ms Gillard replied.

John Della Bosca, the national campaign director of Every Australian Counts, which supports the NDIS, said he was ''over the moon'' after watching Mr Abbott's announcement.

''We have moved very close to saying that the National Disability Insurance Scheme is now inevitable and that's very good news for hundreds of thousands of Australians living with disabilities,'' Mr Della Bosca said.

''I would hope the Prime Minister would continue to progress this bipartisan deal.''

But the president of People with Disability Australia, Craig Wallace, said Mr Abbott needed to clarify his ''conditional'' support.

''The bit that I am troubled by is [Abbott] talking about a temporary levy,'' Mr Wallace said.

''Because that doesn't recognise the core argument of this as an insurance premium for good times and bad. People's disabilities will not go away the next time we have a surplus.''

It was reasonable for Mr Abbott to demand full details on how Labor will fund the NDIS, Mr Wallace said.

But the disability advocate disagreed with the Opposition Leader's suggestion that Labor had not sufficiently explained what disabilities would be covered by the scheme.

''We believe the detail is sufficiently clear and is in what [the Coalition] voted for last year,'' Mr Wallace said.

with Jonathan Swan