US civil rights groups have criticised new laws that could strip millions of citizens of their right to vote in dozens of states across the country.

A wave of restrictive laws passed in Republican-held state legislatures will mean that a disproportionate number of ethnic minorities, people with disabilities, the elderly and the young, will find voting difficult and in many cases impossible.

Among the legislation is a requisite that aspiring voters present a state-issued photo identification card to cast their ballot. That would affect around 21 million people who do not have the ID.

The apparent reason for the ID requirement is to prevent voter fraud, yet an extensive analysis by the US Justice Department.found that incidents of vote fraud are exceedingly rare and that the new laws would not solve the eligibility issues.

Some analysts say the restrictions would have a severe impact on the country's presidential vote in November, favouring the Republican candidate.

Al Jazeera's Rob Reynold travelled to the state of Wisconsin, where he spoke to one woman whose right to vote may have been stripped by the new restrictions.