By Larry Fine

NEW YORK (Reuters) - Two-time National Basketball Association MVP Steve Nash said on Wednesday that predictions of a championship dynasty for the Miami Heat could be premature.

Nash, who led the Phoenix Suns to the Western Conference finals three times, said Tuesday's comeback win by the Mavericks in Dallas, that tied the best-of-seven NBA Finals at 2-2, was proof Miami had their work cut just winning this series let alone future seasons.

"It has been a very exciting series so far. It's amazing Dallas came back and won last night," Nash told Reuters in a telephone interview.

"It's really game on now. It's gonna be a great finish," added the point guard.

When the so-called Big Three of LeBron James, Dwyane Wade and Chris Bosh decided as free agents last summer to join forces in Miami, many pundits predicted they would dominate the game for years, once they got used to playing with each other.

Following some early season struggles, the Heat charged into the NBA Finals, prompting some observers to predict they were already on their way to a long run of championships.

"Well, they could be," said the 37-year-old Nash, who was promoting a June 22 celebrity soccer event in Manhattan's Chinatown to raise money for his foundation benefiting underprivileged children (www.stevenash.org/showdown).

"Obviously they have three dynamic star players who hopefully could grow together. But at the same time, while they could be great, you still have to go out there and do it. They're in a fight right now for the championship.

"Sometimes when you have a few superstars, they can in some ways negate one another. There's only one ball. While they could potentially grow into a dynasty it's definitely not written in stone."

Canadian Nash, who played six seasons for Dallas and was a team mate of the Mavericks' German forward Dirk Nowitzki said he enjoyed the Western Conference champions' style of play.

"Miami obviously is reliant on two or three guys to score the ball," Nash said.

"Dallas obviously has a great leader and scorer in Dirk but they really move the ball well. They play a little more like the European style than we're accustomed to in the NBA.

"It's going to be interesting to see if Dallas continues to find ways to score and at the same time, I think Miami has had their problems scoring down the stretch."

(Editing by Julian Linden)