A Swiss researcher kidnapped almost a year ago in Yemen has been freed and is safe and in good health, the Swiss foreign ministry has said.

The foreign ministry said in a written statement on Thursday that she had been freed on Wednesday with the help of officials from Qatar, who had led the negotiations for her release.

"She is currently in the care of representatives of the foreign ministry and will be returned to Switzerland as soon as possible," spokesman Pierre-Alain Eltschinger said.

The woman, whose name has not been released, was kidnapped on March 13, 2012, in the port city of Hodeida where she worked as a researcher at an institute.

The foreign ministry spokersman added that she did not appear to have suffered any physical injuries.

"Her state of health is overall good, considering the circumstances," he said.

At the time the woman was kidnapped, Yemeni security officials said she had been abducted by tribesmen, but tribesmen in the area denied that, saying instead she had been taken by rebels to the southern province of Shabwa, an al-Qaeda stronghold.

Kidnapping of foreigners is frequent in Yemen, where hostages are used as bargaining chips to secure release of Yemeni prisoners or to get cash.

Eltschinger did not give any details on who may have been behind the kidnapping, nor whether a ransom was paid for the woman's release and did not immediately respond to a request for more details.

He did say, however, that it was help from Qatar that made her release possible.

"The Swiss government expresses its great gratitude to the state of Qatar for having led these negotiations so effectively and ensuring that the Swiss citizen was brought to safety," he said.

Source: Agencies