Israel has announced new charges against World Vision's manager of operations in Gaza just days after he rejected a plea deal and 24 hours before he is due in court over allegations of diverting money to Hamas.

Key points: Mohammed El Halabi is facing trial in Israel for diverting money to Hamas

Mohammed El Halabi is facing trial in Israel for diverting money to Hamas Halabi is now charged with "aiding and abetting" and "passing information to the enemy"

Halabi is now charged with "aiding and abetting" and "passing information to the enemy" World Vision say they have not seen any credible evidence to support the allegations

On Wednesday, Mohammad El Halabi's legal team was advised that new charges had been added to their client's case.

El Halabi is now also accused of "passing information to the enemy" and of "aiding and abetting the enemy in a time of war", with the latter charge coming under the legal article of "treason" in Israeli law.

In August, Israeli Government officials briefed reporters on El Halabi's case, saying they had evidence he funnelled over $43 million dollars of World Vision's budget to the Hamas militant group to pay fighters and buy weapons in Gaza.

The new charges came in the middle of the World Vision official's trial which so far has been closed to the public, diplomats and journalists.

Israeli officials had told western diplomats that the case against El Halabi was "watertight".

But five months since El Halabi's trial began, his legal team say they still have not been given the full evidence file against him.

Despite the seriousness of the initial allegations, the ABC has learnt that Israeli authorities recently offered El Halabi a three-year plea deal.

However, the World Vision official rejected the deal and his legal team said he was planning on pleading not guilty.

A source close to El Halabi's legal team told the ABC the new charges were the result of the Israeli authorities failing to "pressure" him into accepting a plea deal.

"They threatened him with this if he didn't accept the plea deal," the ABC was told.

"This is them saying if you want to play tough, we will play tough."

Sorry, this video has expired Costello 'shocked' by World Vision Gaza manager's charges

'No credible evidence': World Vision

In the new charge sheet, Israel named 35 individuals it says are willing to testify against El Halabi.

Sixteen of them are understood to be serving time in Israeli prisons.

Among the individuals named is Waheed Al Bursh, a Palestinian UN worker who was sentenced to seven months in jail this week for aiding the militant group Hamas in the Gaza strip.

But in a strange twist, Al Bursh has already given testimony to police that he has no evidence of El Halabi committing any crimes, a point he reiterated in a special court hearing yesterday.

The new charges also detail specific incidents where the World Vision official is accused of giving money to Hamas.

One incident detailed accuses El Halabi of allegedly giving "300 Israeli shekels ($105) on a monthly base to a charity managed by Hamas".

Another says the defendant transferred "hundreds of shekels during 2015-2016 to a mosque managed by Hamas".

No details are given of the "millions" of dollars Israeli intelligence officials initially accused El Halabi of diverting.

In a statement World Vision said it was "surprised to see the new charges added at this stage in the process".

"World Vision is anxious to learn the truth behind all the charges, and if evidence of irregularities is found we will take swift and decisive action," World Vision said in a statement to the ABC.

"To date, we have not seen any credible evidence to support the allegations against Mohammad El Halabi. We continue to call for a fair and transparent legal process, which includes the public presentation of all relevant evidence in an open court."

The Israeli Ministry of Foreign Affairs would not comment on why the new charges had been added at such a late stage.

The Australian Government has been following El Halabi's case closely.

Over the past three years the Australian Department of Foreign Affairs and Trade has given $5 million to World Vision aid work in Gaza.

In the wake of the El Halabi charges, all Australian Government funding to World Vision in Gaza has been frozen.

El Halabi is due to appear in court in the Israeli town of Beer Sheva tomorrow in a session that is scheduled to be open to reporters and the public for the first time.