Ducati has been forced to cancel its planned private test with Casey Stoner in Qatar.

The retired double world champion had been due to take part in his second test since returning to Ducati, on Sunday and Monday (March 6-7).

But the MotoGP rules state: "Test riders may test at any circuit, at any time, using only their team's Test Tyre Allocation. Tests are not permitted within the 14 days before a GP event at a circuit unless authorised by Race Direction."

The season-opening race is being held at the same Losail circuit on March 20 and Ducati appeared to believe the 14-day ban referred to the date of the race. However the 'event' is defined as starting on the day of Technical and Sporting controls, meaning the Thursday.

The door was still open for Ducati to seek authorisation from Race Direction. However this would have resulted in protests from other manufacturers had it been granted and the Italian factory has been left with no choice but to cancel the test.

Doubts about Stoner's test emerged yesterday and Ducati announced the decision to cancel this afternoon in Qatar, confirming to Crash.net: "Our scheduled test on 6-7 is now off, the rules are clear on this matter. Unfortunately we misunderstood the situation regarding the dates."

It also seems there is no chance of sending Stoner out on track in this evening's final night of official testing instead: "There is no intention and never has been any intention for him to ride today."

The 14-day ban only applies to private tests, since official tests are open to all competitors. The purpose of the ban is to stop teams booking out circuits for their exclusive use on the days leading up to GP weekends.

Stoner was the fastest Ducati rider on the final day of last month's official Sepang test, where he rode a Desmosedici for the first time since 2010. The Australian had been due to make his debut on the new 2016 machine in Qatar, having used the GP15 in Malaysia.