After complaints from some people, believed to include Prime Minister Tony Abbott, the memorial's council has reversed the decision and ''Known unto God'' will remain.

It is understood Veterans Affairs Minister Michael Ronaldson, who complained in opposition about political interference over appointments at the memorial, complained about the proposed change. Other complaints came from people citing objections on religious grounds or personal animosity to Mr Keating.

Dr Nelson said on Tuesday the original decision, announced in September, was not driven by political correctness. The number of people supporting the original decision far outweighed those criticising it, he said. Dr Nelson said some people claimed the removal of the words was ''de-Christianising'' the memorial but the memorial had always been a secular institution. The remains of an unknown Australian soldier killed in World War I were returned from France in 1993 and buried in a tomb within the memorial to represent all Australians who have died in wars.

Dr Nelson has described Mr Keating's speech as a towering eulogy.

The phrase, ''Known unto God'', was added to the tomb in 1999. The inscription at the southern end - ''He symbolises all Australians who have died in war'' - on a bevelled edge of a stone surround to the grave, will be replaced with identical stone with a variation of words taken from Mr Keating's eulogy, reading: ''He is one of them, and he is all of us.''

Despite claims by some critics, it is understood the memorial did not propose to display the full text of Mr Keating's speech on a brass plate inside the Hall of Memory where the Tomb of the Unknown Soldier lies. It will be mounted outside the hall as planned. Dr Nelson declined to say if he had been contacted directly by Mr Abbott on the issue.

''I think it would be fair to say, knowing Tony Abbott as I do so very well, I suspect he would be quite comfortable with where we've landed,'' he told the ABC. ''I think we've ended up in a very good place, it might have been a bit messy … this was never driven by some suggestion we should remove God or political correctness or anything of the sort.''

The council members were ''in the main a pretty conservative'' group.

''We don't want to create controversy where it's not necessary,'' he said. ''Sometimes you might have, as we had here, 30 or 40 people contact you about something but there is a thread in their concerns that suggests to you that you need to have another look at what you're doing and that's what the council's done.''

Hoardings surround the tomb as the memorial works on the changes, to be unveiled in the presence of Mr Keating on November 11, the 20th anniversary of his speech.