The wins by McConnell and Henderson are significant because they secured a pair of positions for Australia on the mountain bike startline at the Rio 2016 Olympic Games.
McConnell was the hot favourite for the elite men's title, being the third ranked cross-country mountain bike rider in the world and holding an impressive five Oceania elite titles before today's race even started.
The men's field also featured New Zealand National Champion and 2014 Commonwealth Games gold medallist Anton Cooper and Cairns World Cup Cross-Country Eliminator winner Sam Gaze (NZ).
For the first two laps the three men were neck and neck, but McConnell was the first to make a move, going early and pushing hard on lap three.
"It was always going to be really fast off the start with Sam and Anton," McConnell said. "I was able to settle in with them and the pace was fairly inconsistent and fast. It was fairly cat and mouse."
McConnell later rode to a very convincing championship win from Cooper and Australian Cameron Ivory, acknowledging the day's weather was tough on all riders.
"I think at the third lap I was able to get to the front at the start of the climb and put a bit of pace on. Once I was away by myself it was a lot easier to get away and just ride my pace and settle in," McConnell said.
"It was super hard conditions, there's not really any breeze once you get into the trees - I'm not sure you could get much tougher than this."
Scott Bowden took the Oceania title for Australia in the under 23 men's race, after the initial leader Harrison Ersnt (NZ) fell away with a flat tyre early in the race.
(Rebecca Henderson secured a 2016 Olympic position for Australia - Element Photo and Video)
In the elite women's cross-country race, it was the battle of the national champions, with Henderson going head to head with New Zealand Champion Kate Fluker.
The pair led the field for the entire race, with 2014 Commonwealth Games bronze medallist Henderson sitting just in front of Fluker.
For the first half of the race there were only 13 seconds between the two, but Henderson extended this gap to 43 seconds by lap three, creating a lead which Fluker was unable to close.
Despite extreme Queensland heat, Henderson, who has four Oceania titles at the under 23 level, appeared to cruise to her first elite gold medal.
"I'm very relieved to take the win today and obviously take my first Oceania elite title," Henderson said.
"I was able to beat the girls a couple of years ago when I was in under 23's but last year it just slipped away from me and Karen rode away on the last lap so I was watching my back for the whole day today and really working hard."
Three-time consecutive Oceania title winner Karen Hanlen (NZ) secured the bronze.
In the under 23 women's race it was New Zealand's Amber Johnston who took out the Oceania title, moving steadily through the field.