Metro's practice of skipping stations when trains are running late is sometimes a justifiable way for the operator to improve its on-time performance, Victoria's Public Transport Minister Terry Mulder said.

Metro met its monthly punctuality target for a record 25th consecutive month in May, prompting Mr Mulder to boast that Melbourne's trains are vastly more reliable now than they were under the former Labor government.

A total of 92.7 per cent of Metro's trains ran on time in May, an improvement of 10 percentage points on the May 2010 figure of 82.7 per cent. Metro is contractually obliged to run 88 per cent of trains on time each month, or be financially penalised. It receives bonuses for meeting its targets.

Mr Mulder said Melbourne's trains were not yet as punctual as they should be, because the public invested huge sums of money in public transport and deserved a "dividend". He would now push Metro to run 95 per cent of trains on time.