The theft occurred at the premises of Lighthouse Leisure in Southerness overnight last Thursday to Friday.
A static portacabin office was broken into and the safe, which contained a substantial amount of cash, was stolen.
Police are carrying out extensive enquiries and DC Grant Drennan said: “We are currently carrying out door to door enquiries in the area and are keen to trace anyone who may have seen or heard anything suspicious overnight Thursday night/Friday morning.
“It appears that those responsible might have taken some time to carry out this crime and we are also keen to hear about any suspicious activities on the days leading up to this theft. ”
Callers can contact Police Scotland on the 101 number.