Cloth fibres more than 34,000 years old found in a cave in the Republic of Georgia are the oldest fibres known to have been used by humans.

The microscopic flax fibres are the remains of linen and thread, which would have been used in clothing for warmth, for shoes, to sew together pieces of leather or to tie together packs, the team of researchers said.

Archeologists from Harvard, the Georgian State Museum and the Hebrew University excavated the cave, and a paleobiologist at the National Museum of Georgia did the painstaking work of finding microscopic cloth fibres in the soil samples.

The items made from these flax fibres have long since disintegrated, but some of the fibres were twisted, suggesting that they were made into string or rope.

"This was a critical invention for early humans. They might have used this fibre to create parts of clothing, ropes, or baskets — for items that were mainly used for domestic activities," said Ofer Bar-Yosef, an archeologist at Harvard.

Such items would have helped early nomadic humans pack up their gear and move from place to place.

The flax would have been collected from the wild, not farmed, the scientists said. Some of the fibres were also dyed using wild plants.

Prior to this study, published this week in Science, the oldest known ancient fibres were thought to be 28,000 years old, from imprints found in clay objects from a site in the Czech Republic.

The team used carbon dating to determine the age of clay samples taken from layers of the cave. Other flax fibres were found in layers about 21,000 and 13,000 years old.

The archeologists weren't looking for cloth fibres when they began their study in 1996; they were analyzing tree pollen samples as part of their research on environmental and temperature changes that would have affected early humans.

"This was a wonderful surprise, to discover these ancient flax fibres at the end of this excavation project," said Bar-Yosef.