Businessman Johannes Archer, who is accused of the murder of his estate agent ex-wife Rosemarie Vosloo in June, will not be allowed access to his minor son until the boy says he is ready to see him.

That was the order of the Cape High Court on Tuesday in an application by Vosloo's sister, Amelia van der Westhuizen for sole guardianship of the 16-year-old son.

She also asked the court to prohibit Archer from having any contact with her or the boy because she feared Archer might try to hurt him.

The teenage boy was in protective custody shortly after the murder.

On June 23, Vosloo - a Pam Golding estate agent - died as a result of multiple bullet wounds from shots allegedly fired by Archer while she was at a show house in Protea Village, Brackenfell.

Archer, who owns a transport business, applied for bail in the Blue Downs magistrate's court, but his application was refused on July 4. His appeal against that decision was later dismissed in the Cape High Court.

Van der Westhuizen then filed her guardianship application in which she alleged that her sister and Archer had a stormy marriage which ended in divorce in July last year.

She said Vosloo had obtained domestic violence interdicts against Archer during their marriage.

After the divorce, Vosloo obtained custody of the children and Archer was allowed contact with them and had to pay monthly maintenance.

The last protection order she had obtained was an interim order granted on June 20 - two days before she was killed - and it included an order that police confiscate his firearm.

But his firearm was never seized and Vosloo was killed.

Van der Westhuizen said Vosloo bequeathed her entire estate to her children in equal shares, and awarded guardianship to her sister.

But Archer opposed the application and lodged a counter-application in which he asked to be granted full parental responsibilities and rights.

He also asked to have the right to decide who should take care of his son if he was unable to do so himself.

A report filed by a curator indicated that the boy was scared of his father and was not yet ready for a face-to-face meeting. The boy also showed signs of paranoia, the report said.

On Tuesday, the High Court ruled that Archer should remain the boy's legal guardian.

However, it ordered that Van der Westhuizen should be awarded the right to care for and protect the teenaged boy.

Archer will be allowed to contact his son telephonically but will not be allowed to see him until the boy is ready.

Judge Burton Fourie on Tuesday granted the order, which will remain in operation until Archer's criminal case is finalised.