Fears have emerged that rigid quality control in the marking of key stage 2 English Sats could delay the return of test papers to schools.
Markers have to pass a standardisation process - a set of premarked papers that ascertain whether markers are judging standards correctly. If they fail, they cannot mark "live" papers.
Later in the process they have to pass a second set of these benchmark papers.
But members of the TES Connect online forums have said they are not due to get the results of their second benchmarking back until today, and are then expected to send off 70 scripts the next day.
Each script is a complete set of a child's English papers, including a reading test, two writing tasks and a spelling test.
If they continue to mark without knowing whether they have passed, and then discover they have failed, they will not be paid for the papers marked after they took the test.
The exam board Edexcel is running the tests this year, as it did in 2007.
One marker in the North West told The TES: "People feel the whole benchmarking and standardisation process is less supportive than in the past.
"Obviously, they can't just tell us the answers, but without any feedback people fail. By the time they have found out they've failed, it may be the weekend and they have piles of scripts unmarked. They have to be returned to Edexcel. They then have to dispatch them elsewhere."
The Qualifications and Curriculum Authority has said that 30 per cent more markers than required were recruited. An additional 200 markers are in reserve in order to allow for the expected number of drop-outs during standardisation.
A spokesman said: "It's a tough process, but it has to be in order to get the quality standards that we need."
Last year, under the United States company ETS, the return of test papers to schools was delayed and there were concerns about the quality of the marking. The fiasco resulted in the five-year contract being terminated early.