The largest civil rights group in America, the National Association for the Advancement of Colored People (NAACP), is petitioning the UN over what it sees as a concerted efforted to disenfranchise black and Latino voters ahead of next year's presidential election.

The organisation will this week present evidence to the UN high commissioner on human rights of what it contends is a conscious attempt to "block the vote" on the part of state legislatures across the US. Next March the NAACP will send a delegation of legal experts to Geneva to enlist the support of the UN human rights council.

The NAACP contends that the America in the throes of a consciously conceived and orchestrated move to strip black and other ethnic minority groups of the right to vote. William Barber, a member of the association's national board, said it was the "most vicious, co-ordinated and sinister attack to narrow participation in our democracy since the early 20th century".

In its report, Defending Democracy: Confronting Modern Barriers to Voting Rights in America, the NAACP explores the voter supression measures taking place particularly in southern and western states.

Fourteen states have passed a total of 25 measures that will unfairly restrict the right to vote, among black and Hispanic voters in particular.

The new measures are focused – not coincidentally, the association insists – in states with the fastest growing black populations (Florida, Georgia, Texas and North Carolina) and Latino populations (South Carolina, Alabama and Tennessee). The NAACP sees this as a cynical backlash to a surge in ethnic minority voting evident in 2008.

In that year, black and Hispanic voters turned out in record numbers, partly in a wave of enthusiasm for Barack Obama. More than 2 million extra black voters turned out over 2004, an increase of 15%.

Among Hispanics, the upturn was even more pronounced. Two million additional voters attended the polls – a rise of 28% on the previous presidential election.

The scale of the assault on voting rights is substantial, according to experts on electoral law. The Brennan Center for Justice, based at New York University law school, estimates that the new measures could bar as many as 5 million eligible voters from taking part in choosing the occupant of the White House next year.

The 14 states that have embarked on such measures hold two-thirds of the electoral college votes needed to win the presidency. Put another way, of the 12 battleground states that will determine the outcome of the presidential race, five have already cut back on voting rights and two more are in discussions about following suit.

Ethnic minority groups are not the only sections of society at risk of losing their voting rights. The Brennan Center warns that young voters and students, older voters and poor income groups are also vulnerable.

The NAACP says voting rights are being whittled down at every stage of the electoral process. First of all, the registration of new voters is being impeded in several states by moves to block voter registration drives that have historically proved to be an important way of bringing black and Hispanic people to the poll.

Four states – Florida, Iowa, Kentucky and Virginia – continue to withhold the vote from anyone convicted of a criminal offence. In Florida, offenders who have completed their sentences have to wait at least five years before they can even apply to restore their right to register to vote.

Across the US, more than 5 million Americans are denied the right to vote on grounds that they were convicted of a felony, 4 million of whom have fully completed their sentence and almost half of whom are black or Hispanic.

Other measures have reduced the ease of early voting, a convenience that is disproportionately heavily used by African-Americans. Even more importantly, 34 states have introduced a requirement that voters carry photo ID cards on the day of the election itself.

Studies have showed that the proportion of voters who do not have access to valid photo ID cards is much higher among older African-Americans because they were not given birth certificates in the days of segregation. Students and young voters also often lack identification and are thus in danger of being stripped of their right to vote.

In Texas, a law has been passed that prevents students from voting on the basis of their college ID cards, while allowing anyone to cast their ballot if they can show a permit to carry a concealed handgun.

Benjamin Jealous, the NAACP's president, said the moves amounted to "a massive attempt at state-sponsored voter suppression." He added that the association will be urging the UN "to look at what is a co-ordinated campaign to disenfranchise persons of colour."