There is no direct replacement for the OW3394 however the 31VETF series can be used in most applications.
Electronic Timer Controls, Time Delay Switch 250V 10A - 10 minute run-on timer switch for fans / lights, rocker style mechanism.
Also comes in 2000 series 2031VETF.
Please see following link for more information and installation documentation.
https://www.clipsal.com/Trade/search-results?q=31vetf