New figures have revealed Melbourne’s busiest emergency departments turned away ambulances for more than 4300 hours in a six-month period last year.

Victorian health minister David Davis released a report which also shows the city’s 13 biggest hospitals spent a staggering 3052 hours on the Hospital Early Warning System (HEWS) – an unofficial form of bypass.

The Austin, Frankston and Northern hospitals were all on bypass for almost 170 hours each while Monash Medical Centre had 131 hours on bypass and 573 on the early warning system.

The system is used to alert paramedics that a hospital is almost full and should divert non-urgent patients.

The report is the first time the HEWS data has been included with the bypass figures.

"There has been some incentive to classify things as HEWS, which is hidden, as opposed to bypass which is public," Mr Davis told media.

Mr Davis promised the government would strive to "do better".

"The first thing is to get these facts on the table and then hospital managements, network managements, can start to do the work to steadily improve."

The figures come as the Ambulance Employees Australia Victoria union, in its budget submission, stated Victoria needs an extra 266 paramedics, 35 more ambulances and seven new ambulance stations – at a cost of $30 million - to cope with demand.

The union has repeatedly called on the government to invest heavily in the sector, with general secretary Steve McGhie claiming it would reduce pressure on paramedics while bolstering ambulance response times.

The new Victorian Government has promised to spend $151 million on 320 extra paramedics, including 210 in country areas, across the next four years.

Statistics show Victorian ambulances treated 748,834 people in 2009/2010 - up by more than 34,000 people in the previous year.