The number of trains skipping the City Loop has soared this year, new figures show, as Metro resorts to bypassing Melbourne's underground stations at near record levels to avoid running late.

Passengers on the Altona Loop in Melbourne's west have also been inconvenienced by the time-saving technique, in which loop stations are skipped so that delayed trains can get back on schedule.

Metro Trains Credit:Craig Abraham

Loop bypassing forces passengers to switch trains to reach their destination, creating disruption and overcrowding at busy inner-city stations such as Flinders Street and Richmond.

Figures for the first three months of 2015 reveal loop-skipping by Metro has more than doubled in the past year and is at its equal-highest level since records started being kept in early 2013.