Coach Tim Nielsen has asked that the majority of the data from the GPS vests - which are now regularly fitted to Australian players during matches - be kept secret to prevent rival nations gaining crucial intelligence. 'Herald Sun' reported on Monday.

But it has been revealed that Aussie cricketers have produced some remarkable workload data, running up to 29km a day during matches.

Several of them will wear the devices during Tuesday's Twenty20 international against New Zealand in Perth.

Analysis from the GPS devices is helping to determine how player workload should be managed and which players need to be rested to prevent burnout.

Australia says no other country is using similar technology and it will be a secret weapon in preparing for the 2009 Ashes and the 2011 World Cup.

"It will deliver us a tactical advantage and allow us to move forward and plan our workload even better with the next World Cup in mind," a team insider told the 'Herald Sun'.

Using a GPS tracking device attached to the player and relaying information back to a computer, researchers have been able to calculate how much a player runs on the field.

Players' heart rates, the distances they cover and the speeds they reach during a match are fed into the computer.

All-rounder James Hopes clocked a record 29km during a day of Queensland's recent Pura Cup clash against South Australia.

Mike Hussey, Mitchell Johnson and Nathan Bracken wore the GPS equipment during Australia's one-day series in India in October and Hussey and Andrew Symonds used it in the first Test against Sri Lanka in Brisbane.