The mile-high bedroom and copious amounts of state-funded pistachio ice cream may not have been enough for Israel’s first lady. Now it is claimed Sara Netanyahu also pocketed thousands of shekels from recycled bottles between 2009 and 2013.

In what has quickly become known as “bottlegate”, the prime minister’s wife is alleged to have instructed her staff to take empty bottles from state functions, at their official residence in Jerusalem, to a supermarket for recycling – and then hand the cash over to her.

As the prime minister has himself confirmed, in 2013 Sara Netanyahu wrote a cheque to the state coffers for 4,000 shekels (£680), which he maintains is the total sum that had accrued at the residence from the bottles, which Sara had used as petty cash.

However a former employee of the Netanyahus, Mani Naftali, is suing the couple for 1m shekels for various grievances, and claims the amount pocketed is much higher – more like 24,000 shekels. Since Sara Netanyahu is being treated as a private individual and not a government official, state comptroller Joseph Shapira handed the brief over to the attorney general, who has instructed police to begin examining the case – which could end in criminal charges.

In a Facebook post responding to the claims, Netanyahu wrote it off as an old story that is being recycled by the media in an effort to try and topple his Likud party and bring a “leftwing” government into power in next month’s election. Members of Likud’s youth movement held a demonstration outside the Tel Aviv offices of Israeli daily Yedioth Ahronoth last week, to protest what they claim is the media’s efforts to defame Netanyahu.

In a separate matter, the state comptroller announced on Monday that he will publish a comprehensive report on the alleged exorbitant spending by the prime minister at his official residence and the excessive use of state funds for personal consumption.

The report, prepared over the last eight months following complaints, is due to be published on 17 February, exactly one month before the election. Netanyahu’s lawyer, David Shimron, was denied an appeal to have its publication delayed till after the election.

Shapira told the attorney general, Yehuda Weinstein, that there is credible evidence the prime minister committed “a violation of ethics that could amount to criminal offences”, the broadcaster Channel 10 reported. A statement from the prime minister’s office said “it will be proven that everything was done legally”.

The allegations against Sara Netanyahu have opened up the floodgates to speculations on various aspects of the Netanyahus’ lavish lifestyle. Reports said that the PM’s residence spent 100,000 shekels on alcohol over two years.

Tzipi Livni, co-leader of the opposition Zionist Union, took the opportunity to slam Netanyahu. “The price of the alcohol Netanyahu drinks in a month is like the monthly salary of nearly 1 million workers in Israel,” she said at a public event. Netanyahu’s lawyer released a statement claiming that in 2009 and 2010, only 88,964 shekels were spent on booze.

Meanwhile, the journalist Raviv Drucker leaked a draft of another alleged Netanyahu graft case examined by the state comptroller over two years ago, known as “Bibitours”. The report, which has not yet been published, claims that as finance minister a decade ago, Netanyahu’s overseas trips were funded by private individuals and entities.

Yet none of these scandals have affected Netanyahu at the polls, which in recent days show Likud ahead of Zionist Union. According to Prof Yedidia Stern, of the Israel Democracy Institute, there is a large gap between public opinion and the media.

“Israelis don’t trust the media or the legal system,” he says. “Those that have consistently voted for Netanyahu are not doing so because of his personality but because they don’t see any substitute on the right,” he said.