More than a dozen Syrian refugees are on hunger strike in Athens to highlight the plight of 2,000 people waiting for at least six months to be allowed to rejoin families, mainly in Germany.

"Some of us have been here for two years," Fuad, a Syrian father in his thirties, told reporters on central Syntagma Square on Thursday, where the refugees began their strike a day earlier.

"We want to know why we are being held here, as our families in Germany are told that everything is okay for reunification," he said.

Yiorgos Maniatis, one of the protest organisers, said there are more than 2,000 Syrians who have been waiting for more than six months, the maximum period for such family reunions under European law.

Seven Syrian men and seven women are taking part in the hunger strike, three more than began the protest on Wednesday.

On Thursday the hunger strikers were sitting outside bright red tents, each bearing a personal message; "Dreamin' to fly", "I want my family", "We want to settle down."

"What (EU states) are doing is facilitating the work of smugglers," Fuad said.

"We have cases where parents are talking about selling their kidneys to raise money for the journey," he said.

- 'Secret bilateral agreement' -

In May, an official letter leaked by a Greek daily pointed to a tacit understanding between Greek and German migration officials to limit the number of reunification approvals.

"Family reunification transfer to Germany will slow down as agreed," Greek Migration Minister Yiannis wrote to German Interior Minister Thomas de in letter obtained by leftist daily Efimerida ton Syntakton.

Rights groups said the delays were linked to September's elections in Germany, where immigration remains a charged issue.

Athens mayor Yiorgos Kaminis said the government had handled the issue "poorly" by entering into a "secret bilateral agreement" instead of highlighting the issue.

The refugees are fully entitled to reunification under the EU's so called Dublin III rules, Kaminis said, adding that the government "has to assume its responsibilities."

On Wednesday, Mouzalas said family reunifications from Greece to other EU member states had increased 27 percent this year.

But the protesters noted Thursday that permission to reunify, and actual reunification, can be months apart.

"I received permission to rejoin my family in Germany on March 1. I am still running between asylum offices (in Athens) with three minors in tow," Syrian mother Hilal Bidal told reporters.

"It would have been better to stay in Syria. Had we died there, at least we would have had dignity," she said.

Another woman said: "I have been here with four children for two years. We are prepared to die here if we do not get our rights."

The Syrians' families in Germany also intend to demonstrate for reunification in a week's time, Maniatis said.