Key parts of the Old Testament may have been compiled earlier than previously believed, according to a new analysis of ancient texts found on pottery shards.

The shards, which have been dated to 600 BC and contain inscriptions written by at least six different people, show the ancient Kingdom of Judah had a high rate of literacy, meaning it was possible for the books ranging from Deuteronomy to II Kings to have been written down during the First Temple period.

The finding may have decide a key question of whether the oldest books in the Bible were written before Judah and its capital of Jerusalem were destroyed in 586 BC - an event followed by the exile to Babylon.

The research findings, which were revealed last year, were published in a US journal this week.

Professor Israel Finkelstein, of Tel Aviv University's Department of Archaeology and Ancient Near Eastern Civilizations and research co-leader, said there is a "heated discussion" over the timing of the composition of a "critical mass of Biblical texts".

"But to answer this, one must first ask a broader question: What were the literacy rates in Judah at the end of the First Temple period? And what were the literacy rates later on, under Persian rule?"

The pottery shards were found at an excavation in what was the remote border fort of Arad, now located in modern Israel. The inscriptions relate to instructions for troop movements and food expenses and are not believed to have been written by professional scribes.

Professor Finkelstein said that extrapolating from what they have found at Arad, "we can estimate that many people could read and write during the last phase of the First Temple period".

"We assume that in a kingdom of some 100,000 people, at least several hundred were literate," he said. "Following the fall of Judah, there was a large gap in the production of Hebrew inscriptions until the second century BCE, the next period with evidence for widespread literacy. This reduces the odds for compilation of substantial Biblical literature in Jerusalem between (about) 586 and 200 BCE."