RYANAIR boss Michael O'Leary has refused to give evidence in a German court case probing the budget airline's employment practices.

A German labour court in Wesel has cited the Ryanair chief executive to appear personally on July 1 in relation to the case brought by a former pilot, who has raised a complaint against the carrier's recruitment arrangements and its use of the London-based human resources firm, Brookfield Aviation International.

However, the Irish airline confirmed that Mr O'Leary would not attend the hearing.

A spokeswoman for Ryanair said: "Ryanair doesn't comment on individual employment cases. We can confirm that our CEO will not be in Germany on July 1 as these matters are routinely handled by Ryanair's Personnel Department and our lawyers."

The pilot says he flew with the airline as a self-employed contractor, an arrangement which enabled Ryanair to avoid normal social security obligations such as holiday pay and sick pay.

The relationship between Ryanair and Brookfield Aviation came under scrutiny in 2013 when the employment agency failed in its bid to sue members of the Irish Airline Pilots Association for not serving their full notice period.

The low-cost airline, which has a maintenance base at Prestwick Airport and also flies from Glasgow and Edinburgh Airports, hires the majority of its pilots through Brookfield Aviation.

The agency creates "mini-companies" and then appoints each pilot as a director. Pilots then hire out their services to Ryanair on a self-employed basis, rather than being directly employed by the airline.

These unusual arrangements were the subject of a recent study by the University of Ghent which found that, on average, one in six European pilots were now on "atypical" contracts, especially those employed by low-fares airlines.

Ryanair, Norwegian and Wizz Air were named among the worst offenders, but Ryanair has disputed the findings and criticised the methodology of the study which was based on an anonymous online survey of 6,600 pilots.