Multi-millionaire Mr Sunak said he would "of course" release information on his tax affairs, but could not say when his return would be released.
“That is the established precedent and I’d be very happy to follow the precedent," he said.
“In terms of timing, I will have to speak to the Cabinet Office and figure out the right way that happens. But yeah, I have no problem doing that.”
He said that "of course" this would happen in his first year in No 10.
Rishi Sunak through the years - in pictures
Mr Sunak pledged to publish his tax return during his unsuccessful Tory leadership campaign during the summer.
His family’s finances came under intense scrutiny when he was chancellor, when the “non-domiciled” status of his wife Akshata Murty was revealed.
The arrangement reportedly saved her millions in British taxes while the cost of living soared.
The billionaire’s daughter who married Mr Sunak in 2009 is thought to be worth hundreds of millions of pounds and the couple made the Sunday Times Rich List in May, with a combined fortune of £730 million ($870m).
Rishi Sunak's childhood landmarks - in pictures
Ms Murty’s tax status typically applies to someone who was born overseas and spends much of their time in the UK, but still considers another country to be their permanent residence.
While the non-dom status is legal, critics said it looked bad at a time when the then-chancellor increased the tax burden on the British public.
Indian relatives of UK Prime Minister Rishi Sunak celebrate his new job - video
Mr Sunak said his wife was entitled to use the arrangement because she was an Indian citizen and planned to move back to her home country to care for her parents.
After the controversy, Ms Murty said she would pay UK taxes on all of her worldwide income.