North Carolina's Republican governor has pledged to fight a lawsuit filed by the Department of Justice in response to a measure that introduces some of the most stringent voting laws in the country.

Governor Pat McCrory said that the lawsuit, which warns that the new restrictions are intentionally designed to set the clock back by discouraging African Americans from exerting their democratic rights, is without merit.

The lawsuit, lodged with a federal district court in North Carolina on Monday, calls for four key provisions of the state's new legislation to be blocked on grounds that they would have a discriminatory effect on minority voters. It also calls for the state to be put back into a form of federal oversight – or "pre-clearance" – that was removed in June when the US supreme court struck down elements of the Voting Rights Act that had been a cornerstone of race relations in the US since 1965.

Announcing the legal challenge, the attorney general Eric Holder said that allowing North Carolina's new restrictions to stand would be "inconsistent with our ideals as a nation ... This is an intentional attempt to break a system that was working; it defies common sense."

Holder said he had brought the action, which follows a similar move against a Republican-led voting clampdown in Texas, "more in sorrow than in anger." He added that the federal government would "not hesitate to use the tools and legal authorities at our disposal to fight against racial discrimination, to stand against disenfranchisement, and to safeguard the right of every eligible American to cast a ballot."

The challenge to North Carolina is the latest attempt by the Obama administration to hold back the tidal wave of right-wing activism that was unleashed by the supreme court's ruling in Shelby v Holder in June. Under that judgment, delivered by the five Republican-appointed justices against the unanimous opposition of their four Democratic-appointed peers, the pre-clearance provision of the Voting Rights Act was knocked down, removing a crucial weapon in the fight against race discrimination in America.

Under that provision, known as section 5, designated states largely in the South of the country had to receive federal approval, or pre-clearance, for any change they wanted to make to voting laws. The section was conceived to prevent Southern politicians from using sleight of hand to disenfranchise black people, such as imposing poll taxes or requiring trivia tests in polling stations.

As the lawsuit points out, North Carolina had an active history of discriminating against black voters from about 1900 to about 1970. More recently it has been impeded from carrying out the most blatant discrimination by virtue of the fact that 40 of its 100 counties were required to pre-clear changes to voting laws – a safeguard that was removed by the supreme court in its Shelby judgment.

North Carolina has a voting-age population that is 68% white and 21% black. In recent years, voter turnout among African Americans has improved dramatically, partly because of the popularity of Barack Obama in the 2008 and 2012 presidential elections and partly because of the introduction of a range of voting provisions that encouraged greater participation such as early voting days.

But the new restrictions contained in the North Carolina House Bill 589, which was signed into law last month, threaten to undo those advances. The four elements of the law that the DoJ's lawsuit tries to block are:

* the imposition of one of the most narrowly imposed voter ID schemes that would remove the vote from those who cannot produce authorised photo identification;

• reduction in the number of early voting days through the elimination of the first week of such extended polling;

• abolition of same-day voter registration during the early voting period;

• banning the counting of provisional ballots cast by voters in the wrong precincts.

The DoJ suit points out that African American voters would be disproportionately affected by those provisions. In 2012, 71% of black voters who participated in the presidential election cast their ballot during early voting.

One of the main ways to meet the tough new voter ID rules is to show a photo card issued as a driving licence. Yet black households in North Carolina are three times as likely as white households to lack access to a vehicle – 14.3% compared with 4.3% respectively.

McCrory said Monday he has hired a private lawyer to help defend the new law from what he suggested was a partisan attack by President Barack Obama's Democratic administration. "I believe the federal government action is an overreach and without merit," McCrory said at a brief media conference during which he took no questions. "I firmly believe we have done the right thing. I believe this is good law."

Myrna Perez of New York university's Brennan Center for Justice called the North Carolina clampdown "one of the most regressive new laws" to be introduced since section five of the Voting Rights Act was killed. "It is extraordinarily restrictive and it would be a huge step back for North Carolina."

Perez added that the current legal battle over the state's voting intentions underlined how necessary the pre-approval system had been as a safeguard against discriminatory practices. Now that it was removed, "there's going to have to be a great deal of effort put into these lawsuits to have the same effect," she said.

The Associated Press in Raleigh contributed to this report. © Guardian News and Media 2013