The Prime Minister yesterday responded directly to the Aboriginal leader's call for a ''national conversation'' on a new date for Australia Day.

At Canberra's Commonwealth Park, Mr Rudd the Prime Minister who said sorry for the Stolen Generations looked at Professor Dodson, sitting just metres away, and said, ''No''.

But an unfazed Professor Dodson last night made good on his pledge ''to talk to Australians about a lot of things this year''.

Adding to the ''invasion day'' debate he'd sparked 24 hours earlier, the indigenous leader called on Mr Rudd to ''go beyond'' his pledge to hold a referendum to recognise Aboriginal people in the constitution's preamble.

''I think we should go further ... and put something in the operative parts of the constitution,'' Professor Dodson said.

The Australian National University law academic said changes could be made to entrench values of equality and remove ''blatantly racially discriminatory'' sections such as one which allows states to ban people from voting on the basis of race.

''I mean, why do we need to do something like that in our constitution in this modern age?''

On Sunday, Professor Dodson used his new position to question the wisdom of January 26 being the national day, because many Aborigines saw the landing of the First Fleet in 1788 ''as the day on which our world came crashing down''.

Mr Rudd responded just as directly yesterday, saying the idea to change the timing of our national day wouldn't float.

''To our indigenous leaders, and those who call for a change to our national day, let me say a simple, respectful but straightforward no,'' Mr Rudd told a citizenship ceremony audience

''We are a free country and it is natural and right from time to time that there will be conversations about such important symbols for our nation.

''It is equally right as a free country that those of us charged with political leadership provide a straightforward response.''

''I can understand that for some Australians, indigenous Australians particularly, this day has mixed history for them,'' she said.

ANU Professor Jon Altman said he believed his colleague Professor Dodson had made a good point.

''I think this is a bit close-minded by the PM. It wouldn't surprise me if the majority of Australians wanted to keep it, but lets not pre-empt the answer,'' he said.

''A mature nation should be able to discuss these things, we should have a conversation about these things. But if we did have another day, the issues of substance [to indigenous Australians] wouldn't change.''

with AAP