Malcolm Turnbull has declared Prime Minister Scott Morrison must “deal with the Peter Dutton issue” after revelations a Chinese businessman paid tens of thousands of dollars to a former Liberal minister to secure a one-on-one meeting with the then-immigration minister.

The former prime minister made the extraordinary claim on Tuesday after a 4 Corners report revealed that former Liberal MP Santo Santoro was paid to organise a 2016 meeting between businessman Huang Xiangmo and Mr Dutton in a private suite of a Chinese restaurant in Sydney.

Mr Dutton, the Home Affairs Minister, has denied offering any special treatment for the family of the Chinese Communist Party-aligned billionaire as part of a back-room campaign to win Australian citizenship. Mr Huang ultimately failed in his citizenship bid after ASIO objected to his Communist Party links.

But Mr Turnbull, who blames Mr Dutton for sparking last August’s leadership spill that cost him the PM’s job, insisted the Minister had questions to answer as he is “responsible for domestic security”.

“It is very troubling. The allegation is that a lobbyist, a close factional ally of Mr Dutton’s, Santo Santoro, received money in return for securing privileged access to the Minister on behalf of Mr Huang – and all of that in circumstances where there has been rising concern about lobbyists, about foreign influence,” Mr Turnbull said.

“Peter Dutton has got a lot to explain about this.”

Former prime minister @TurnbullMalcolm has asked Home Affairs Minister Peter Dutton for an explanation, amid allegations of special treatment for a Chinese billionaire who was seeking Australian citizenship. #auspol pic.twitter.com/FPml8tMi8H

— The New Daily (@TheNewDailyAu) April 9, 2019

Mr Turnbull said he introduced legislation tightening the rules on foreign influence and interference in late 2017, in response to rising community concerns.

“This is the national security of Australia. Remember the furore that arose against Sam Dastyari? All the same issues have arisen again and this has to be addressed at the highest level of security, priority, urgency by the Prime Minister. The buck stops with him,” he said.

“I know what it is like to be Prime Minister and, ultimately, you are responsible. So Scott Morrison has to deal with this Peter Dutton issue.”

Mr Dastyari resigned as a Labor senator in January 2018, more than a month after revelations of his own close ties to Mr Huang. At the time, the government labelled him a “Chinese agent”.

Monday night’s ABC TV report also revealed that Mr Dutton gave approval in 2015 for then-Senator Dastyari to conduct a private citizenship ceremony for Mr Huang’s wife and two children.

The ceremony allowed Mr Huang’s family to expedite their citizenship by weeks, or even months. Mr Dutton approved it after Mr Dastyari told him the family urgently wanted to travel overseas, the ABC said.

On Tuesday, Mr Dutton told The New Daily he was introduced to Mr Huang as a leader in Sydney’s Chinese community “and had lunch with him on that basis”.

“I have never met or spoken with him since that time. I have certainly never made representations on his behalf to the department or anyone else,” he said in a statement.

“Mr Huang has not been granted citizenship and I won’t comment on ASIO matters. Suffice to say I fully support the action they have taken [in recommending his citizenship be denied].”

The 4 Corners report also detailed recordings in which Mr Santoro, now a lobbyist, claimed Mr Dutton was one of his best friends and that he could provide clients access to staff in Mr Dutton’s office for a payment of at least $20,000.

“There is nobody else anywhere who is better placed than me to help you through this particular part of the project, nobody. I can go to somebody in the Minister’s office and say ‘Can you have a close look at this?’,” Mr Santoro is recorded stating.

Mr Dastyari told the program he wrote to Mr Dutton asking him to grant the Huang family expedited citizenship.

“I thought there was a snowflake’s chance in hell that this was going to get approved, and the pace and speed at which it got approved at the time surprised me, and in hindsight concerns me,” he said.

On Tuesday, Mr Turnbull said he did not know if granting the Huang family’s citizenship had been expedited as a result of that ceremony.

“The first I learned about it was in the media … If such a fast-tracking of Mr Huang’s family’s citizenship application was, in fact, made, it was made by Mr Dutton,” he said.

Mr Turnbull warned that his successor, Mr Morrison, could not ignore the controversy.

“Scott Morrison is the Prime Minister and you can’t wave this off and say it is all part of gossip and the bubble,” he said.

“I think it is very, very concerning and very troubling for anyone – and I would say that is every Australian who is concerned about ensuring that our politics is not influenced by foreign actors, and that our politics and political decisions and access are not available to be hawked around in the way that it is alleged it was.”