Barnaby Joyce, who leads the National Party, apologised on Saturday for comments he made in March 2021 while he was a backbencher.

In a news conference in Sydney, he said the remarks sent in a leaked text message were "based on assumption and commentary" and also claimed that he personally apologised to Mr Morrison, before offering his resignation as deputy prime minister.

But Mr Morrison did not accept his resignation, he added.

The text message said: "He is a hypocrite and a liar from my observations, and that is over a long time. I have never trusted him and I dislike how he earnestly rearranges the truth to a lie."

However, Mr Joyce said today: "Your views from the backbench are based on assumption and commentary, not on a one-on-one relationship.

"And basing something on commentary is a flawed process. Dealing with someone one-on-one in the hardest job in the nation is something entirely different."

The 54-year-old added his opinion of Mr Morrison changed after becoming deputy prime minister.

He said: "To actually be in a room with a person when you're dealing with such things as AUKUS, the pandemic, how we make our nation a stronger place, gives a vastly greater insight than your life totally at the back of the chamber.

"And so, it was based on assumptions - not fact. I should never have written the text, so the fault is mine.

"I never expected the text to be forwarded on, I certainly never expected it to be in the public realm. But none of it would have ever happened had I not written it."

Mr Joyce also said the comments in the text messages would have damaged Mr Morrison.

"I wouldn't be apologising for it if you didn't think that there was something wrong with it."

Speaking about Mr Morrison, Mr Joyce said that on a "one-on-one working relationship, I found a man who has honoured every agreement that he's made with me".

Mr Joyce's National Party is a junior coalition member in Mr Morrison's government, which is expected to face a general election later this year.

Mr Morrison has not made a statement about the comments or resignation offer.