(Reuters) - Michigan's attorney general has asked a federal appeals court to reinstate a law banning straight-ticket voting - the practice of using one mark to vote for all candidates from one party - in time for the November general election.

The law, passed by Michigan's majority Republican legislature and signed by Republican Governor Rick Snyder, was temporarily suspended in federal district court last month. A coalition of civil rights and labor groups had argued that it would keep African-Americans from voting.

On Wednesday, Attorney General William Schuette, also a Republican, filed two emergency motions with the U.S. Court of Appeals for the Sixth Circuit, saying the law would not place a burden on voters or violate the U.S. Voting Rights Act, as the coalition had alleged in a lawsuit aimed at overturning the legislation.

"Forty other states ban straight-ticket voting and no case anywhere has ever suggested it was unconstitutional or violative of the voting rights act," Schuette wrote in the motions.

He has asked for the law to be reinstated in time for the November presidential election, while the lawsuit is being fought in court.

The Michigan law is among a number of state voting rules that have been fought in the courts ahead of the November election, along with stricter voter identification laws in some states and laws on the voting rights of felons in others.

Citing a report by a specialist with the U.S. Census bureau that found that African-Americans were more likely to use straight-ticket voting than white voters, U.S. District Court Eastern District of Michigan Judge Gershwin Drain last month granted a preliminary injunction sought by civil rights and labor groups who sued Secretary of State Ruth Johnson in an effort to overturn the law.

Straight-ticket voting, often favored by labor groups and political parties who recommend voters support a slate of candidates, was common in the United States for much of the 20th Century.

Opponents complained the practice made it difficult for voters who wished to choose among candidates of different parties and that removing the option forces voters to make decisions based on criteria other than party affiliation.

Today, only nine states offer voters the option of voting for a party's entire slate with one mark, according to the National Conference of State Legislatures.

(Reporting by Sharon Bernstein; Editing by David Gregorio)