The 79-year-old, who led Australia between 1996 and 2007, was on his daily walk near his Sydney home on Wednesday when he saw a couple fighting, The Sunday Telegraph reports.

After breaking up the row, Mr Howard waited with the woman until police arrived.

"How good is John Howard? He's obviously been a mentor to me and others, particularly on our side of politics. It shows the character of the bloke," the prime minister told reporters in the Northern Territory.

Mr Morrison used the incident to point out the government's $350 million investment in tackling domestic violence.

"John Howard gave us a reminder that we've all got a responsibility when it comes to this," he said.

"If you see this stuff going on, call it out like John did."

Former Labor prime minister Kevin Rudd, who ended Mr Howard's reign at the 2007 election, also publicly congratulated his former opponent.

"Well done John Howard. Any violence against women is unacceptable," Mr Rudd tweeted.

As a result of the incident, a 44-year-old woman was charged with breaching an apprehended domestic violence order and granted conditional bail to appear at Manly Local Court on Tuesday

The man, 47, was taken to hospital as a mental health precaution.

1800 RESPECT (1800 737 732)

Lifeline 13 11 14

Australian Associated Press