extra holiday entitlement
-- is suggested in Gyldendals Røde (Fagordbog).

There is an example here:
http://www.eurofound.europa.eu/eiro/1999/12/feature/dk991216...

Working time

The government intervention in the disputes of 1998 largely centred on extra holiday entitlement, granting at least two extra days of annual holiday, as well as two (rising to three) "care days" for workers with families. This clearly increased expectations prior to the negotiations in 1999, when unions demanded an extra week of holiday entitlement - which would have increased total annual entitlement to six weeks (five weeks are guaranteed by law) - or, as a minimum, the same increase in time off as awarded in the DA/LO area in 1998.
....

I always find it difficult to explain or translate!