World No.2 Swiatek made short work of Czech Katerina Siniakova on John Cain Arena on Monday, advancing 6-3 6-4 in an hour and 21 minutes.
The pair swapped breaks of serve in the first set before Swiatek stuck her nose in front to clinch the opener.
The left-handed Siniakova continued to match it with the five-time grand slam champion in the second set but slipped at 3-all and couldn't recover.
"It wasn't an easy first round so I'm happy that I'm through," Swiatek said in her on-court interview.
"I know her from playing doubles against her so she's not an easy opponent.
"She was playing really well and I just had to be more proactive when I wanted to and at the end, in the second set, I did that."
Swiatek pulled out of the tour in September for "personal reasons".
It was later revealed she had accepted a one-month ban after testing positive for a banned heart drug, which the Pole said came from ingesting a contaminated non-prescription medication.
She will meet Rebecca Sramkova in the second round after the Slovak battled back from a set down to beat American Katie Volynets.
Following her third-round exit at Melbourne Park last year, Swiatek can return to world No.1 if rivals Aryna Sabalenka and Gauff fall in the early stages of the Open.
Reigning French Open champion Gauff earlier continued her recent red-hot run of form, beating fellow American and 2020 Australian Open champ Sofia Kenin 6-3 6-3 to power into the second round.
Coco Gauff was all business in her first-round win over Sofia Kenin at Melbourne Park. (Joel Carrett/AAP PHOTOS)
Gauff was not at her absolute best was still too good for world No.74 Kenin, who is a shadow of the player who won her maiden grand slam title at Melbourne Park in 2020 then reached the final of the French Open later that year.
She had also beaten Gauff in two of their previous three meetings - both at majors - but was unable to match it with the No.3 seed in the key moments.
Gauff, 20, has won her past 10 matches in succession and is riding a 19-2 win-loss run dating back to late September, including title triumphs at the recent United Cup in Sydney - where she beat Swiatek in a spicy decider - the WTA Tour Finals in Saudi Arabia and the China Open.
"It was a tough match for me today," said Gauff.
"I knew it was going to to be difficult, but I'm happy with how I played.
"I could have dealt with the second serves better, but I could hardly see at one end (due to the sun)."
Gauff mixed 12 aces with nine double faults.
Sofia Kenin fought hard but came up short in her clash with fellow American Coco Gauff. (Joel Carrett/AAP PHOTOS)
Gauff's next opponent will be Britain's Jodie Burrage, who downed French qualifier Leolia Jeanjean 6-2 6-4.
In other round-one action, two-time former champion and 21st seed Victoria Azarenka could not replicate her surprise run to the semi-final in 2023, falling 6-2 7-6 (7-2) to Italian world No.76 Lucia Bronzetti.
American No.12 seed Diana Shnaider ousted Italy's Elisabetta Cocciaretto 7-6 (7-4) 6-4 and No.28 seed Elina Svitolina from Ukraine downed Romania's Sorana Cristea 6-4 6-4.
US Open runner-up Jessica Pegula overpowered Australian youngster Maya Joint in straight sets as did 10th seed Danielle Collins in her clash with Ukrainian qualifier Daria Snigur.
Swiss Belinda Bencic, returning after becoming a mum, ousted Latvian 16th seed Jelena Ostapenko 6-3 7-6 (8-6) while 17th seed Marta Kostyuk also advanced, downing Japanese qualifier Nao Hibino in three sets.
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