Overcrowding on Melbourne's train network has hit a record high in the morning peak, a new survey has revealed.

Figures released by Public Transport Victoria showed that across the network about 20 per cent of morning peak services were overcrowded during the survey period.

Twenty per cent of Melbourne morning trains are overcrowded. Credit:Justin McManus

However, during the PM peak that figure only reached about 7 per cent.

The survey was taken over 14 week days in May this year.