Tony Abbott's "knightmare" start to 2015 could eventually cost him the prime ministership but his political failure would come at a quantifiable price for Barnaby Joyce: $700,000.

The Agriculture Minister has boldly "bet his house" on Mr Abbott leading the government into the next election during an interview with the ABC.

According to title deeds and transfer documents, that means he is willing to stake $700,000 on the durability of Mr Abbott's leadership.

Documents show that Mr Joyce and his wife Natalie paid $700,000 in January last year for their family home on an acreage block south east of Tamworth.