Tony Higgins, chief executive of the Universities and Colleges Admissions Service (Ucas), said figures released yesterday showed that university places were being filled at a record pace.
Nearly 222,000 students had had their places confirmed compared with 219,465 at the same time last year.
There has been a drop of 4,000 in the number awaiting decisions. Admissions officers dealt with a record 10,000 calls on Thursday and more than 5,000 by lunchtime yesterday, yet only a "handful" reported problems caused by industrial action.
"You can deduce that the Association of University Teachers' action is having no effect at all. We are either ahead of where we were last year or we are level. The 4,000 drop must be either because the number of applicants is down or because more have had their conditional offers confirmed."
A union spokeswoman said: "It is very difficult for us to show that inaction is happening but we are absolutely sure that our members are taking action. It is only happening in some institutions. We were not trying to stop the system but to bring our case for higher pay to people's attention."
Several hundred students are receiving their history and general studies results late, schools said yesterday, because an exam board has not sent details of their grades.
Quentin Langley, a spokesman for the OCR board, said that a few results slipped through the net every year. "We do our best to get everything sorted out within a day or two. We are aware that this is a very stressful time.
"Last year, out of 220,000 results there were problem with about six or seven hundred. We are expecting that this number will be down this year." He said about half the problems with exam results turned out to be the fault of schools.
Diab Khudari, a pupil at Hinchingbrooke School in Huntingdon, Cambridgeshire, had not received his chemistry result, from the same board, by yesterday morning.
Diab, who scored As in maths and biology was desperate for his result because he has so far failed to secure a place at medical school and wanted to go straight into the clearing process, which matches students to unfilled places.
For Simon King, a student at Long Road Sixth Form College, Cambridge, who missed his grades for a place to study environmental science of the earth and atmosphere at Reading University, initial desperation turned to happiness. He had an offer of a place if he got a B and two Cs, but scored two Cs and an E.
Anne King, his mother, said: "He rang the university and spoke to the person who interviewed him, who remembered him and said he could still have his place."
t Queen Elizabeth Grammar School in Ashbourne, Derbyshire, was omitted from our list of the top 50 comprehensives at A-level yesterday. The school scored 22.9 points per candidate which would have placed it in 15th position.