the 81-year-old went into Sydney's Royal North Shore Private Hospital for routine health tests.
It is believed the check-up is not related to COVID-19.
A spokesperson for Mr Howard's office told News reporter there is no concern for his health.
His office said he is having checks as a precautionary measure but did not say what the checks were for.
The health issue is not thought to be related to coronavirus.
Five years ago the former Liberal Party leader was treated for blocked arteries at Royal North Shore Hospital in Sydney and had two stents inserted.
Mr Howard was prime minister from 1996 to 2007.
His most notable achievements include bringing in new gun laws after the Port Arthur massacre and introducing the nationwide value-added tax.
On his 80th birthday last year, he said: 'I feel the same as I did yesterday.
'I'm very happy to be alive and to have had the privilege of being born in Australia.'
In April Mr Howard said Scott Morrison is handling the coronavirus crisis 'very well' and that the pair regularly spoke on the phone.
