Hillsong pastor Brian Houston has conceded he now “genuinely doesn’t know” if Scott Morrison wanted him to be invited to the White House state dinner after previously rejecting the suggestion as “nonsense”.

On Thursday, Houston denied having heard anything about the prospect of attending the state dinner until the Wall Street Journal contacted him three weeks before and said he has still not discussed the matter with Morrison.

Morrison has never contradicted the report that he wanted Houston to attend, instead dismissing it as “gossip” and refusing to answer in parliament by arguing it is a “matter for the White House” who attended the dinner.

Senate estimates has so far failed to produce answers. On Monday officials from the prime minister’s department took questions about Houston on notice and on Thursday Department of Foreign Affairs officials said the “indicative and partial list” they had seen on 4 September did not include Houston’s name.

Houston told 2GB Radio he knew Morrison “well before he was in politics” but refuted suggestions he is a “mentor”, noting that Morrison had said only that Houston was one of “several pastors who were a blessing to him” in his first parliamentary speech.

Houston said his contact with Morrison since he became prime minister was limited to a text asking him to “pray for Jen, his wife, and two kids”, Morrison’s attendance at the Hillsong Conference in July, and a coffee and thank you text thereafter.

Houston said he had “never heard” about the suggestion he may be invited to the White House state dinner, both before and since.

“To answer the question: was I invited? I genuinely don’t know,” Houston said.

“At first I thought: well no I wasn’t – because it was news to me – now I literally don’t know because the prime minister and I have never had a conversation about that.

“And the reality is I couldn’t have been there anyway because I already had prior commitments for our church in London for its 20th anniversary.”

Asked if it were possible someone in the prime minister’s office had put his name forward, Houston replied: “Everything’s possible, I just don’t know because I’ve never had a conversation with the prime minister about it.”

Houston said he was “confused” when the Wall Street Journal contacted him three weeks before the dinner and replied “no, it’s incorrect; it’s not true [because] as far as I was concerned it wasn’t true”.

“I just didn’t believe it, because I’d never heard anything about it so I thought it was nonsense.

“But then I guess the fact I didn’t know anything about it doesn’t tell us whether I was or wasn’t invited.

“But it’s a matter for Scott Morrison because I genuinely don’t know the answer … I haven’t talked to him about it – before the state dinner or since the state dinner, I haven’t talked to him at all actually.”

Asked why he hadn’t asked Morrison after the report, Houston replied he believed Morrison had “a whole lot more important things” to worry about, including drought.

The Hillsong pastor also denied knowledge of a recording of his paedophile father Frank Houston preaching in 2004, five years after being banned because of his crimes.

“That’s news to me,” he said.