Sources say Japan's education ministry has decided to postpone the introduction of private-sector English tests as part of a new university entrance exam system starting next April.
Under the new system, applicants would take two private English tests between April and December.
The tests are operated by six entities, including Benesse Corporation and the Eiken Foundation of Japan.
Officials were due to begin accepting requests on Friday for the identification numbers needed to take the exams.
Analysts say the ministry made the decision after taking into account the possible negative effects on the more than 500,000 examinees.
Critics say private tests vary in difficulty, making it hard for universities to use the scores when considering applicants.
Only about 60 percent of universities and junior colleges had planned to use the scores in the first year of the new system.
Students say they are worried about the high costs of sitting for the tests and are frustrated that officials have not yet announced venues and other details.
Education minister Koichi Hagiuda made a controversial remark in October that was taken to condone perceived unequal opportunities for education.