Barnaby Joyce insists he was making a political point when claiming Bill Shorten had left miners "for dead".
The Labor leader has demanded the deputy prime minister apologise in parliament for comments that appear to make light of Mr Shorten's role as a former union boss during the Beaconsfield mine disaster in 2006.
Mr Joyce told reporters on Monday the opposition leader was not standing up for mine workers as Indian mining giant Adani weighed up whether to proceed with its Carmichael coal project in Queensland.
"I remember Mr Shorten - didn't he stand outside a goldmine down in Tasmania.... He put on the hi-vis shirt and the bomber jacket, told us all how he was with the working man," Mr Joyce told reporters.
"Well, he is not with them now. He has left them for dead."
Mr Shorten labelled the Nationals party leader a "disgrace" on Twitter before taking to the floor of parliament to respond.
"This is not a random comment from a Twitter troll, this is the person who is meant to be the deputy prime minister of Australia," Mr Shorten told MPs.
He called on Mr Joyce to stand up in parliament and apologise to the family of Larry Knight, the miner who died at Beaconsfield in April 2006.
"(They) didn't need this whole thing dragged up again by the thoughtless comments of the deputy prime minister of Australia."
Mr Joyce told parliament no one, including journalists who attended the press conference, had drawn the same inference from the comment.
"The inference ... is completely and utterly out of order," Mr Joyce said.
"I have the greatest respect for Larry Knight who, at 44 years old, lost his life, and not once would I besmirch his character."