Seven people will appear in the Johannesburg Magistrate's Court on Monday on charges related to the murder of Gauteng health department finance officer Babita Deokaran.

Deokaran was shot outside her home in Mondeor, south of Johannesburg, on Monday morning. She died in hospital later that day.

She was a witness in an investigation into alleged fraud relating to a R300-million tender for personal protective equipment (PPE).

The seven were arrested on Thursday in a joint operation between the police and private security companies.

Last week, Gauteng Premier David Makhura said information Deokaran brought to light had led to dismissals and the institution of civil claims to recover public funds from businesses and government officials responsible for malfeasance and corruption.

Her murder sparked fears over the safety of witnesses in corruption cases.

The Special Investigating Unit (SIU) said there were around 300 witnesses in the PPE tender investigation - and it would wait for court processes to unfold before deciding whether her murder was directly linked to the probe.

The single mom had just dropped her child off at school when she was shot.

The Sunday Times reported that her murder involved a high degree of planning, while the arrests also reportedly involved a high level of tracing.

Some of these details could be revealed during a bail application.

Meanwhile, Shafique Sarlie, the lawyer for the accused, told News24 that he had to fight "tooth and nail" to see his clients.

According to Sarlie, he had been trying since Friday to gain access to his clients.

"The Hawks have been giving me the runaround. They denied me access to my clients," he told News24 on Saturday.

"They made me wait over two hours. I had to threaten [them with] an application to the high court before they allowed me in."

He said the law states that an accused can see a lawyer immediately after an arrest.

Police spokesperson Captain Ndivhuwo Mulamu said no one is prevented from seeing clients who are in custody, but investigators were verifying the information of the seven when their lawyer arrived.

"I spoke to one of the investigators, who said they were busy with the suspects and verifying a whole lot of information. They wouldn't intentionally refuse him access to his clients," she said.

"Remember that a person taken in custody is asked by police if they would want to call anyone to inform them of their arrest; everyone is allowed to talk to their lawyer," she said.

The seven are understood to be between the ages of 24 and 31.