Several students contacted The TES after the first tests last month to say that it was possible to use a calculator for checking sums in the mental arithmetic section. Candidates used the same answer book as for the written element, where calculators were allowed.
But the Teacher Training Agency said it had decided not to change the test format after investigating students' results in the previous round and finding no quantitative evidence of cheating.
It would not have been practical o allow test booklets to be collected mid way through the tests, a spokesman said. It would be the responsibility of the 80 test centres to make sure that students did not cheat, he said.
The latest tests, offered the first chance for a re-sit for those who failed in the first round on June 1. Those who fail for a second time to get 60 per cent have three more chances next year. Some 1,400 students have applied for this week's resits, an increase on the 1,145 trainees who failed last month's test.
Some are believed to have boycotted the first round in protest at the way the exams were implemented. Ninety-five per cent of students passed at the first sitting.