Transport Minister Andrew Constance has fired back at Sydney University for insisting that a shake up of the rail timetable will seriously impact thousands of students and staff, saying they will in fact benefit from a boost to "turn-up-and-go" train services.

In a letter to the university's vice-chancellor, Michael Spence, Mr Constance said students and staff would benefit from trains on the T2 Line between Strathfield and Redfern running every five minutes on average in peak periods of the day.

"Contrary to your statement that 10,000 students and staff in Western Sydney will be disadvantaged, the 2017 timetable introduces an additional 1500 services across the network," he wrote to Dr Spence.

"Your staff and students will benefit from 'turn-up-and-go' services on the T2 Line."