A member can be available for the labour market in a period between two periods in a n education, if the period is over 4 weeks. However, dagpenge cannot be paid if the unemployment is due to the holiday period at the University (for example summer holiday), that is, it is only the period between two stages of a "total education".
Therefore it is not possible to receive dagpenge if you just continue on a master after the summer-holiday.
But if the period between your bachelor and master is over 4 weeks and not due to normal holiday period, you can maybe get dagpenge, but only if no salary or SU is paid to you during the unemployment period. Finally, you cannot get unemployment benefits if you are a free student member. If you meet all above mentioned requirements, you must pay normal membership fee to be able to get dagpenge.
Even if you do not meet these requirements for having benefits in the period between bachelor and master, then it is always strongly recommended to join an A-kasse at latest 2 week after finishing bachelor. If you - within 2 years - decide to interrupt the master education, then you will be eligible for benefits according to your graduate status obtained with the bachelor.
This also applies if you want to take study leave from your master study within 2 years.
Still possible to have free study membership
You can also get free study membership while studying at the master education and during study leave. However you only have up to 5 years in total of free study membership. Read more about free membership for students.
When / if you become a master candidate later
When you become a master candidate, you can choose to be admitted (again) as a new graduate. Then you start all over again in the unemployment benefit system and are entitled to a new, full unemployment benefit period of 2 years that must be spend within 3 years.