Mercedes has until October to decide if it will enter Formula E as a customer team for the 2018-19 season.
Last October, FE and Mercedes-Benz Grand Prix signed an agreement guaranteeing Formula 1's top constructor an entry into the electric single-seater series.
Mercedes, which remains contractually committed to F1 until the end of the 2020 season, said the electrification of the automotive industry would "make Formula E very relevant in the future".
A decision is yet to be made on whether Mercedes will take up its option to enter FE for 2018-19, although if it does it will not be with its own powertrain technology.
The FIA has already approved the list of eligible constructors for that season, which means Mercedes would need to lease a powertrain – motor, gearbox and inverter – from an approved manufacturer.
This would mean entering by proxy, possibly with specialist customer team HWA, ahead of a fully-fledged Mercedes team and powertrain combination.
Formula E CEO Alejandro Agag told Motorsport.com: "I think the interest [from Mercedes] is very strong but for 2018/19 if they come, they are not registered as a manufacturer.
"They will need to be a client of somebody. For 2019-20 they could come as a manufacturer still.
"We'll see what they do, they still have their option until October, they can choose to exercise it or not. If they exercise it they will be a client."
The powertrain manufacturers confirmed for 2018-19 are BMW, DS, Abt (Audi), Mahindra, Renault, Jaguar, NextEV, Penske Autosport and Venturi.
To avoid aligning itself with a more traditional rival constructor like BMW, a Mercedes team could strike a deal with Venturi, which is due to partner German car part manufacturer ZF for its 2018-19 powertrain.
Mahindra, NextEV and Penske would also be more neutral options than one of the more established brands.