A former solicitor of the Sydney Lindt cafe siege gunman says Man Haron Monis claimed he was being "set up" by ASIO and "picked on" by Australian Customs officials about his frequent trips abroad, an inquest has heard.

The coronial inquiry is continuing to examine Monis's background, including his early life in Australia, in a bid to understand the motivations behind December's fatal Martin Place siege.

In later years Monis became involved in multiple disputes with government departments and made increasingly strange claims about his background.

Franklin Arguedas, who acted as Monis's solicitor in the mid-2000s, said his client claimed he was a high-ranking official back in Iran.

He told the inquest Monis said he was being unfairly targeted by the Australian Security Intelligence Organisation (ASIO) and bothered by Australian Customs officials.

Mr Arguedas said he did not know why Monis travelled so often, but he once flew to New Zealand and back in a day to "bamboozle Customs, to make people believe that he was doing something".

Monis also told Mr Arguedas he "knew the whereabouts of an individual that was wanted by Israel" and together they could claim a reward of $1 million to $2 million from the Israeli government if Mr Arguedas was the "front man".

Mr Arguedas said he declined the offer.

"I thought he was harmless, but I thought he might have a scheme like those Nigerian emails that you get from time-to-time," he said.

Mr Arguedas said he believed at the time Monis was fabricating stories, but that he was not psychologically damaged "to the point that he might be insane".

However, he said he did recommend Monis seek therapy, and Monis reacted angrily.

"I just thought this guy wanted to be someone. He wanted to be a big person," Mr Arguedas said.

Monis believed Customs may have been "wantonly targeting Muslim clerics" after the jailing of Schapelle Corby in Indonesia, where Islam is the dominant religion, Mr Arguedas said.

He said Monis also believed they were seeking "revenge" after terrorist Abu Bakar Bashir, a radical Muslim cleric, received a light punishment for his role in the 2002 Bali bombings.

A former employer of Monis's, Hassan Zoabi, also gave evidence at the inquest.

Hassan Zoabi, a former employer of Man Haron Monis, said Monis was softly spoken and did his job well. ( AAP: Dean Lewins )

He said he employed Monis, then known as Manteghi, as a supermarket security guard in the late 1990s.

Mr Zaobi was a caretaker manager at a shopping centre in Greenfield Park.

He told the inquiry Monis was softly spoken and talked about being well connected in his home country of Iran and "related to people who were rulers in Iran at the time".

"He kept on telling me that Iran was going to be making headlines on the world stage soon," he said.

"Monis asked a lot of questions about how government worked in Australia. The same questions, over and over.

"He was always thinking ... if he wasn't talking to anyone, you could tell he was deep in thought."

However, he "did his job very well" and was good with people, Mr Zoabi said.

"He just had that thing about him where you straight away knew he was polite. He was softly spoken," he said.

Catherine Wood, an Amnesty International manager who met Monis in 2010, described his "delusional self-importance", including his outrage the Queen did not personally respond to a letter he wrote her.

Monis had come to Amnesty with complaints about threats he received from the public after he was charged for writing offensive letters to the families of soldiers who died in Afghanistan.

"He addressed all his comments to the [male] refugee case worker and none at me, even though I was the one conducting the interview," Ms Wood said.

"It was very much like he was standing on a soapbox [and] painting himself as a noble victim."

Monis rejected by Rebels bikie gang who saw him as 'weird'

On Monday the inquest, held by NSW coroner Michael Barnes, heard evidence about Monis's life history, mental state and "unpersuasive and unsuccessful" attempts to gain a following in Australia.

Monis attempted to join the Rebels motorcycle gang in one of many acts that point to a life spent trying to "achieve significance", the inquest heard.

He was described as a man constantly striving for power and influence and a sexual predator who used a "spiritual healing" business to sexually assault women over many years.

Lawyers assisting the commission also described Monis's history of mental health issues, but said it was unlikely to "provide a full answer to the questions about his motivations for the siege".

Counsel assisting the inquest Sophie Callan said Monis actively sought to become involved with the Rebels Motorcycle Club sometime in 2012 or 2013.

She said he had dealings with the club's Mount Druitt chapter, but they saw him as "weird".

Counsel assisting the inquest, Jeremy Gormly SC, told the inquiry that in the months before the Sydney siege, Monis's life was spiralling downwards as he faced debt, a criminal record and further criminal charges.

The inquest is being conducted across numerous sessions throughout the year, with the current session scheduled to last a fortnight.

Police officers, as well as customers and staff taken hostage at the Lindt cafe, will take the stand during the course of the inquest.

But the inquiry heard the cafe hostages would not be giving evidence in this or the next segment of hearings.