President Barack Obama won the support of an estimated 2.3 million of Asian American voters to Republican challenger Mitt Romney's estimated 900,000 votes, or 71% to 28%, according to a new poll.

However, the country's fastest growing ethnic group is not wedded to either party, according to the survey released Wednesday by the Asian American Justice Centre, Asian & Pacific Islander American Vote and the National Asian American Survey.

Obama's biggest break came among voters whose top issues were immigration, the environment and civil rights, but the most important issue to all voters surveyed was "economy and jobs".

According to the post-election survey, 46% of registered voters polled and 43% of those who voted in the 2012 election said they do not identify with either major party.

"Still, one of the persistent dynamics of the Asian American electorate is its continued potential for persuasion by candidates of either party," the poll said.  In a raft of current and projected swing states - including North Carolina, Virginia and Florida - the Asian American population's explosion in the last decade has outpaced the national average.

The poll notes: "In 2008, about 600,000 new Asian Americans entered the electorate, and we anticipate a similar increase in 2012, approaching 3% of all votes cast."

The projected share of the Asian American vote in 2016 will continue to increase, the poll found. Asian American voters increased from 1.6% of the total vote in 1996 to 2.5% in 2008.