The dispute comes less than two years after the library moved into its �511m headquarters at St Pancras.

The series of one-day strikes by staff who load books onto the new building's automated delivery system could last for a month.

A high-tech system delivers books to reading rooms

A statement on the library's Website says books cannot be retrieved from environmentally secure basement rooms without the staff.

Management are believed to be uncertain how many of the 150 employees will arrive for work and the library says the closure will be reviewed after a week.

The statement said: "The library has been in discussion with the staff concerned for some months over the library_s wish to introduce more flexible working patterns in its reading rooms.

"These are intended to provide better services for readers, permitting full advantage to be taken of the new facilities at St Pancras."

Underground fear

Members of the Public and Commercial Services Union (PCS) fear the proposals will reduce earnings and damage health and safety.

They say extra money paid during the library's move from Bloomsbury is to be ended.

The union also says half the staff involved will be forced to work full-time in four basements rather than rotating between reading rooms and underground duties.

PCS Joint General Secretary John Sheldon warned: "The management plans will damage the quality of service to library users and could put the collection at risk."

He said they had offered talks at the conciliation service Acas, which the library had refused.

A library spokesman promised further dialogue with the union and a re-opening of the six humanities reading rooms as soon as possible.

The library's office will remain open but advance reservations will also be suspended.

The British Library's move to St Pancras has been controversial as delays meant a rise of �350m in building costs compared to original 1970s estimates.