Heta-Morris, 25, debuted at the world champs last year - becoming the first Kiwi to do so - and placed 11th in his weight class.
He believes he is better off for the experience and is aiming for a top-seven finish this time around.
"I know what to expect and I know what world-class hands feel like."
Heta-Morris said he had changed his training regime this year and was feeling more confident than last year.
"Last year I had no-one to train with and ... had just started lifting weights," he said.
Now he trains four days a week at the gym, with 50kg dumbbells, and one day a week with training partner Monty Corbett arm wrestling.
Heta-Morris started competing less than three years ago, and has since become the New Zealand and Oceania champion.
In comparison, next month he will be up against guys who have been competing for more than a decade.
"The disadvantage I have is they get to train with world-class pullers and they learn from each other," Heta-Morris said about the stiff competition.
"And there is really no one here to teach us except YouTube."
Mobile users click for video
Heta-Morris is still raising funds for his trip to Lithuania, and said it can be hard without proper sponsors. He believes he can go far in the sport but needed help.
"It has taken a big toll out of family time, I work full-time and train in the mornings so it is pretty hard," he said.
"If I had a full sponsor I could go really far, I could dedicate more time to training and still have time with family."
Heta-Morris said representing New Zealand at the world champs last year was a great feeling and he was looking forward to doing it again.
He will be competing in the super heavyweight class (over-110kg class) and will favour the right hand competition.
Heta-Morris said an arm wrestle could last as long as 40 seconds but usually they were decided within the first couple of seconds.
Heta-Morris is currently supported by local companies Skin Graft, Insurance Towers and Kiwi Kai. Other local companies have also given generously for the $2000 raffle.
To help Heta-Morris get to Lithuania you can buy a $10 raffle ticket from Kiwi Kai on Amohau St, or donate through his Givealittle page. Also check out his Facebook supporter page: Maateiwarangi "The Beast" Heta-Morris. An arm wrestling event day is also being held at Kiwi Kai next Saturday from 2pm to 4pm.