The incident, which has prompted claims of intimidation and bullying, comes as Peter De Angelis has lodged a new development application to build a pub near a public school in Casula.

His first attempt was rejected by Liverpool Council in the face of a community backlash and petition by students.

Former policeman and insurance fraud investigator David Seedsman stood in front of the group, two-thirds of whom were women and children, as they met in a Casula cul de sac on Wednesday night, refusing to leave when asked.

"I understand that I am not welcome, but I just want to listen and make sure you say things accurately and make sure you don't defame the De Angelis family," Mr Seedsman says he told the group.

When the Casula Community Group for Responsible Planning's spokeswoman, Criss Moore, told him he was intimidating the group, he denied this, and said he was allowed to be in a public place.

When the group decided to leave and move to a private house, Mr Seedsman followed them down the street.

He said the flashing device in his pocket was a mobile phone, not a recording device, as claimed by the residents in a complaint about the incident to Liverpool Council.

"I was making sure she wasn't getting people to sign the petition based on information that wasn't accurate," he told Fairfax Media.

The group has complained to the council in a letter: "The intimidation tactics caused many of the adults and children present (some of whom had escaped their former countries because of similar intimidation and oppression) to be very fearful."

The letter alleges Mr Seedsman drove past several times as they met in private. He denies this.

Mr De Angelis said Mr Seedsman did human resources and legal work for the company.

"David was there purely because in the past this group has publicised information that was absolutely incorrect. He was asked to go along to make sure what was spoken about was accurate," he said.

Mr De Angelis said there were "significant concessions" in his new development application, with the proposed pub now closing at 12, no bottle shop, a children's play area within the hotel, no live entertainment, security patrols of the carpark and a courtesy bus.

The community group says it has been unable view the application.

Greens NSW MP John Kaye was critical of the De Angelis group's attempt to stop criticism of its application, which is required to prove there is no adverse social impact from the pub.

"The Casula community has every right to organise its entirely lawful opposition to the De Angelis proposal free from harassment or surveillance. This is a group of residents desperate to protect their neighbourhood," said Dr Kaye.

"If these tactics are the only way to secure approval for a late-night liquor and gambling operation in a residential neighbourhood, then the proposal is clearly without merit and should be rejected."

The De Angelis group is meanwhile fighting NSW Police in court to block police from releasing data on violent incidents at the company's Macarthur Tavern to the Casula community group.

The Macarthur Tavern in Campbelltown is on the annual list of violent venues published by the Baird government, with 12 serious assaults recorded in 2015.

NSW Police had agreed to release more data in response to a freedom of information request.

But Mr Seedsman claims the police data is "not accurate" and creates a poor impression of the hotel because it shows hundreds of incidents. "The statistics are inflamed," he said.

The NSW Civil and Administrative Tribunal will hear the matter next month.

Dr Kaye was critical of the Baird government's proposed changes to the liquor and gaming regulator, which will prevent community members who live more than 100 metres from a venue from appealing against a new pub.