The finding has emerged from a survey carried out by the Association of Teachers and Lecturers. The union is quizzing 400 entrants to the profession on the merits of the new-style induction year, introduced by the Government last September.
New staff now have the right to a reduced timetable, a mentor, and an action plan. Their work is observed and assessed and any teacher who fails the induction year is forced to leave the profession.
Within weeks of the programme's launch, claims were made that schools were failing to deliver it properly, mainly because of funding shortfalls.
A survey of 43 new teachers on an induction training course at London's Institute of Education found more than half did not have a reduced teaching timtable and many were missing out on mentoring.
However, the first 100 responses to this latest survey show that about 80 per cent of new teachers like the mentoring system.
Meryl Thompson, the union's head of policy, said: "We are still in a very preliminary stage of analysis but the majority of responses state that the quality of mentoring is meeting teachers' needs.
"But that still leaves 20 per cent who are unhappy about mentoring in their schools."
Ms Thompson said that although there was an assumption in the Government plan that mentors should be trained, there was no training programme, nor was there funding set aside to pay for one.
The full survey will be published in April. New teachers were also questioned about target-setting, classroom observation, and the quality of informal support.