Labor has promised $12 million in funding over four years to the National Library of Australia for it to resume adding new content to its online database Trove.

Trove allows people to access collections of books, photographs, newspapers, maps, and historical documents online.

The database was launched in 2009 and since has digitised millions of records from the library's own collection as well as items from state and local collections.

The Coalition Government has made cuts to a number of national cultural institutions in Canberra, including the National Library.

Recent budget estimates papers state the National Library will shed 28 staff as the result of a $20 million funding cut.

The Library previously said would not be able to keep adding to the database without dedicated funding.

Shadow Arts Minister Mark Dreyfus said it was essential Trove continued to be funded.

"It's an absolutely invaluable resource for historians, school teachers, for academics," he said.

"It's unique in the world, it's a national treasure and it has to go on being added to.

"It needs to keep adding to the items that are available to make it as complete and as full a resource as possible."

Trove has more than 20 million unique users every year including museums, libraries, galleries, historical societies and research bodies.

Mr Dreyfus said Trove was a resource worth continuing.

"We're going to have to examine carefully how the damage that's been done by those cuts can be repaired, but this one can't wait," he said.