Israel's President Reuven Rivlin has warned new legislation that could allow Jewish-only towns could be discriminatory.

In a letter published Tuesday, he said he feared the controversial Nation-State Bill would harm Jews around the world.

The bill, which being debated in the Knesset, declares that Israel is “the national home of the Jewish people” and collectively have a “unique” right to self-determination in the land.

Among other things, it would relegate Arabic — currently an official language alongside Hebrew — to “special status” and allow communities to exclude potential residents based on “religion or national origin”.

The bill “has no balance” and “could harm the Jewish people and Jews around the world and in Israel, and could even be used by our enemies as a weapon”, Mr Rivlin said.

He added that lawmakers should “take a look at Israeli society and ask: in the name of the Zionist vision, are we willing to support discrimination and exclusion of men and women based on their ethnic origin?”

Eyal Yinon, Knesset legal adviser, said the bill should not be approved in its current form because it "deviates significantly from the delicate balances required."”

Clause 7b of the bill says: “the state can allow a community composed of people of the same faith or nationality to maintain an exclusive community.”

Mr Rivlin said this clause “would essentially allow any community to establish residential communities that exclude Sephardic Jews, ultra-Orthodox people, Druze, LGBT people. Is that what the Zionist vision means?”

Concerns were also raised by Attorney General Avichai Mendelblit, who said the bill raised constitutional problems.

The first version of the bill was approved in a first vote by the Knesset in April.

The committee for advancing the bill will meet on Tuesday to approve a final version, but the meeting could be postponed if there is no agreement on the clauses of concern.

A source involved in process told Haaretz: “There’s a 50 percent chance that we’ll succeed in reaching understandings in the next few days. That’s a higher chance of passing the law than we’ve had until now.”