Thirroul JFC's club house at Gibson Park has been broken into on the eve of the Junior Registration Day on Saturday. 

Officials discovered the break while collecting stock for the registration day during Friday night's training session for the Thunderbirds women's teams.

The incident follows a break in at Thirroul Surf Club in the early hours of Wednesday morning, during which a defibrillator and $900 in cash were stolen and the patrol room ransacked.

In comparison, Thirroul JFC's club house suffered minor damage and it does not appear at this stage that anything of significance has been stolen, besides some new match balls.

This includes shorts and socks, which will be available at the registration day at Thirroul Bowling, Recreation and Leagues Club between 10am and 2pm on Saturday.

Anyone with information about the break ins is encouraged to contact Crime Stoppers on 1800 333 000 to assist with the police investigation.