World Rugby introduced tough sanctions on high tackles earlier this month in a bid to improve player safety.
Leo feels the new regulations may compromise the traditional strengths of players from the Pacific Islands, who are renowned for their physicality.
"My main concern is it will eventually restrict our employment opportunities," Leo told BBC 5 live.
"There are long-term implications that these laws could have, not just on us as individuals, but on our economies long term."
Leo, who won 39 caps for Samoa as well as representing Wasps, Perpignan and London Irish, has set up a programme to help with the welfare of Pacific Island players in England.
It is estimated that around 18% of all professional rugby players worldwide are of Fijian, Samoan, or Tongan heritage, with 72 playing in the English Premiership.
And Leo feels education is key if those from the islands are going to continue to thrive.
"We are going to have to start tackling lower, and being a lot more conscious of those risky tackles," he added. "We are going to have to look at ourselves.
"We can't just be known as the enforcers and the guys renowned for those big hits.
"We are going to have to do that within the laws; the laws are constantly changing, and there is a lot of work to be done in the process of re-educating ourselves."
Leo fears Pacific Island players may suffer more than most under the new guidelines, which will see yellow and red cards awarded for reckless challenges to the head area.
It's estimated around 18% of all professional rugby players worldwide are of Fijian, Samoan, or Tongan heritage
"One of the big things we have on our hands is trying to break down that perception we are dirty players," added Leo.
"The only thing that really differentiates Trevor Leota and Brian Lima, who retired in the mid-2000s, from Chris Hala'ufia and Mat Luamanu - who has had three red cards in the past year - is the times and the laws.
"I don't think players are tackling any harder than they were back then, but the game has moved on. It's definitely an education process that needs to happen outside what is being offered.
"There is a fair bit of concern around. The majority of Pacific Island players in the Premiership have been brought over here to do a job that seems to have been frowned upon now.
"There is going to be a lot of work in re-defining how we play."
And Leo feels Pacific Island players could be lost to rugby union if the new tackle sanctions reduce their effectiveness.
"The game had to change, and it had to get safer, but there are a lot of other sports which Pacific Islanders could play," Leo said.
"We have all of these other sports contending for our players: the rugby league NRL, American Football, boxing.
"The reason rugby is so attractive to Pacific Islanders is the contact element, and if we aren't going to get our [contact] fix through rugby, then we will get it elsewhere."
Photo: Getty Images (Dan Leo played for London Irish in the 2014-15 Premiership season and is a former Samoa international with 39 caps)