Sunsuper and Kinetic Super will merge in late 2017 pending a "comprehensive due diligence process", according to a joint statement by the two funds.
If the merger goes ahead it will create a new $45 billion industry fund with 1.3 million members.
Kinetic Super board chair Frank Gullone said the merger would lead to lower fees as well as "enhanced services and products to all members".
"The two funds are highly complementary and share similar values. We are united by our profit-for-member model and unfaltering focus on maximising members’ retirement savings within a low-cost and transparent structure," Mr Gullone said.
Sunsuper chair Ben Swan said there was a "strong cultural fit" between the two funds.
"With the shared objective of always acting in our customers’ best interests, a successful merger will drive future efficiencies, promote a stronger competitive position in the market and ultimately generate greater value for the combined member and employer base," Mr Swan said.
The joint statement said that while the final decision to merge had not been made, both boards are "committed to the successful conclusion of the merger".
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