The sole Jewish member of the Iranian parliament will accompany President Hassan Rouhani when he travels to New York next week for the UN general assembly.

Siamak Moreh Sedgh, who represents Iran's Jewish community in the majlis, the country's parliament, will try to help Rouhani revamp the Islamic republic's image on the world stage after eight acrimonious years under previous president Mahmoud Ahmadinejad, who issued controversial statements about the Holocaust.

The move comes after Rouhani pledged to work to improve civil rights for Iranian minorities and provide a bigger role for them in government when he was sworn in to office in August.

Sedgh and Ahmad-Reza Dastgheyb, a Muslim, are the only MPs travelling with Rouhani to the UN, local agencies reported. After the constitutional revolution, which took place between 1905 to 1907, Iranian Jews were given a reserved seat in the parliament which they have retained after the 1979 Islamic revolution.

After Ahmadinejad's departure from power, Rouhani appears to have started an initiative to tell the world that Iran, whose official religion is Islam, is not against Jews. Rouhani's Twitter account, believed to be run through his office, surprised many recently by posting a Rosh Hashanah blessing for the Jewish new year. Iran's foreign minister, Mohammad Javad Zarif, followed in Rouhani's footsteps by tweeting a similar blessing.

"Our Jewish countrymen are a recognised minority in Iran and have an active representative in the parliament," Zarif told the semi-official Tasnim news agency after his tweet in early September, according to Tehran Times.

"We were never against Jews. We oppose Zionists who are a small group," he said. "We do not allow the Zionists to represent Iran as an anti-Semitic country in their propaganda so they can cover up their crimes against Palestinian and Lebanese people."

Iran is believed to have the largest Jewish population in the Middle East after Israel. The country's Jewish population declined after the Islamic revolution as many of its members emigrated to Israel or other countries around the world.

Only officially-recognised religious minorities are represented in the Iranian parliament. Like Jews, Zoroastrians also have a reserved seat but Christians have three, mainly because of their bigger population. The Baha'i faith, which was founded in Iran, is banned and its members are the most persecuted religious minorities in the country, with no access to higher education.

Sedgh succeeded a famous Jewish Iranian MP, Mauric Motamed, in 2008 and has since been able to retain his seat. Sedgh's visa for the US has not yet been issued.

Zarif's tweet attracted a great deal of attention. He also responded to a tweet by Christine Pelosi, the daughter of the US politician Nancy Pelosi, who had told the Iranian minister that the Jewish new year "would have been sweeter" if Iran ended its Holocaust denial.

Zarif posted to her: "Iran never denied it. The man who was perceived to be denying it is now gone. Happy New Year." The Iranian foreign minister was referring to Ahmadinejad.