The Melbourne 19-year-old swept the time trial at Mt Helen on Wednesday - capturing gold in the two categories with a command performance.

Gigante had a 9.1-second cushion over reigning champion Grace Brown in the elite category and more than two minutes to spare over her nearest under-23 rival with the one ride.

Gigante also completed the double in last year's road race in the FedUni Cycling Australia Road National Championships.

This is the third year in a row she has stamped her authority on the nationals, bursting onto the scene with a clean sweep of the under-19 road race, criterium and time trial in 2018.

In addition to her road race double last year, she also won the under-23 time trial.

While ecstatic with her performance, Gigante expressed disappointment that her new Tibco-Silicon Valley teammate Shannon Malseed was missing from the championships owing to injury.

"I'm really sad to be here without her."

The Ballarat-based Malseed was ruled out of the titles after a heavy crash in the Bay Crits at the weekend.

Gigante said she could not believe she had ruled the road in the time trial, given she had not previously beaten any of the other riders to finish in the top five.

"I'm absolutely stoked."

She said while she had trained really hard for the time trial, after finishing seventh in the event last year a top five finish in the elite had been her primary objective.

Gigante had only praise for the new course set in and around the Federation University precinct.

She said it had a "bit of everything" and was more technical than the previous circuit south of Buninyong.

Gigante said being able to stay with her uncle and aunt who lived near Buninyong to train regularly on the course had been of assistance.

She was sure if she had not done that she would not have secured the gold medal.

Gigante was uncertain what winning the title might do for her chances of being selected for the time trial at the Tokyo Olympic Games this year.