Barnaby Joyce says he will support the Turnbull government’s National Energy Guarantee on the condition that all Liberal Party member’s of parliament buy his book.

The former deputy prime minister, who has reserved the option of crossing the floor to oppose the plan, made the demand of Energy Minister Josh Frydenberg by phone on Saturday evening.

Mr Frydenberg is understood to have assured Mr Joyce that he is doing everything possible to convince party members to buy the book.

The Turnbull government has said it will buy the book once it has hit the shelves and fallen in price.

“All we have to do is wait, and the price will fall,” Malcolm Turnbull told reporters.

But Mr Joyce was not satisfied with post-release purchasing of his book saying the government needed to commit to the full retail price if he was going to vote for the NEG.

“I’ve named my price at $29.99,” said Mr Joyce.