Author Peter Trickett said the display of cartographic treasures from around the world ignored key evidence - in the form of early maps - showing that Europeans voyaged to Australia more than 200 years before the arrival of Captain James Cook.

The Canberra-based former journalist said it was strange that while the exhibition opened a new world to tens of thousands of visitors, the library's authorities had stored reproductions of two 16th-century French maps, believed by some to be based on earlier Portuguese voyages to the continent.

Mr Trickett said the 1547 Vallard Atlas depicted the east coast of Australia, although clarity was not helped by the signature habit of the cartographer - whose name is lost to history - who put north at the bottom of his maps, giving them an upside-down appearance.

The library said there was not enough space in the exhibition for facsimiles and that it had prominently displayed original examples of the ''Dieppe tradition'', from which the two reproductions come.

However, historians who believe the Dieppe maps were based on actual voyages to the southern seas, rather than cartographical speculation designed to dazzle the crowned heads of Europe, are in the minority. But that, said Mr Trickett, was not the point.

''Strangely, these two important maps have been omitted from the exhibition, despite the fact that the NLA claims to show a complete history of the mapping of the Australian continent from early times to the present,'' he said.

''This omission makes a mockery of its claim.

''My central theme is not that the NLA necessarily has to agree that its map evidence proves the Portuguese discovery, but that as a national institution it has an obligation to show all of its relevant map evidence - not just the part of it that suits a preconceived view - so that visitors to the exhibition can make their own judgment.''

Mr Trickett's book expanding on his theory of Portuguese exploration of Australia has been published both at home and in Portugal.

The library's Curator of Maps, Martin Woods, said the exclusion of the two Dieppe reproductions made space for two magnificent originals from the same tradition borrowed from the British Library.

''I really wanted to include more to tell the story of Dieppe but we got these two originals from the British Library and we feel that by bringing in lots of facsimiles we could have told lots of stories with four or five hundred items,'' Dr Woods said.

''Unfortunately we only have room for 138 items in the whole exhibition.''

The curator also pointed out that Mr Trickett had been a speaker at a pre-exhibition ''discovery day'' at the library that featured writers with different opinions on the Dieppe maps, followed by a viewing of the facsimiles.