Hunter, who's enjoyed a fine championships after also battling through qualifying to reach the singles main draw, proved in a different league alongside Belgian ace Mertens as they crushed China's Shuai Zhang and American Caroline Dolehide 6-1 6-1 in Friday's semi-final.
The third-seeded pair have been so dominant in their run to the final that they have dropped just nine games in their surprisingly easy campaign.
In their second match, Hunter and Mertens were given a walkover because of injury to one of their opponents as they led Romania's Irina-Camelia Begu and Ukraine's Anhelina Kalinina by a set.
And they got another straight passage in the third round when Marketa Vondrousova, the singles semi-finalist, decided to pull out from the doubles to save herself for her last-four meeting with Elina Svitolina.
Now, following the men's final on Sunday, they'll start as big favourites to lift the title against the veteran pairing of Czech Barbora Strycova and Taiwan's entertaining but unorthodox Su-Wei Hsieh.
With the rain beating down outside, the Australian Storm blew hot under the No.1 court roof as she and Mertens, a brilliant double act who have already won the Italian Open together this year, broke serve five times on their way to wrapping up the easiest of victories in five minutes under an hour.
Hunter is the world's No.7 at doubles, which has long been her speciality while also trying to improve a singles career which has shown such promise, especially when she proved the mainstay of Australia's charge to the Billie Jean King Cup final last year.
She's the first Australian to appear in the women's doubles final at Wimbledon since her compatriots and friends Ash Barty and Casey Dellacqua got beaten in 2013 by a different duo featuring Su-Wei Hsieh. That year, she was partnered by China's Peng Shuai.
If Hunter wins, she'll be the first Australian victor in the event since Rennae Stubbs partnered Zimbabwean Cara Black to a triumph in 2004.
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