SERIOUS doubts have emerged about the case of Peter Spencer, with the NSW farmer's family saying his 47-day hunger strike concerns more than land-clearing.

Graham Spencer, Peter Spencer's brother, criticised the politicians, reporters and activists who have turned his brother into a cause, saying they did not know the full story.

According to The Australian, Mr Spencer's remarks are a swipe at, among others, Nationals senator Barnaby Joyce, who publicly took up Mr Spencer's cause.

The issue provoked a public split between the Coalition partners, with Liberal senator Bill Heffernan describing Mr Spencer's protest as "barbaric" and urging that he be pulled down.

But as Graham Spencer called for his brother to end his 47-day hunger strike, saying his family's overriding concern was for his health, fresh information emerged about the NSW farmer's past, including an armed stand-off with police 40 years ago.

The Australian understands the incident occurred in August 1970 following the breakdown of Mr Spencer's first marriage and was an attempt to "get some attention".

Mr Spencer reportedly suffered a minor bullet wound to his chest, believed to be self-inflicted. Graham Spencer said yesterday his family was deeply concerned for Mr Spencer, who claims to be subsisting on water, lemon juice, vitamins and pain killers.

He said while Australia's Kyoto obligations and legislation such as the Native Vegetation Act had restricted his brother's use of the land, they were not his only problems. "It's something that's come up after the trouble started," Graham Spencer told The Australian.

Mr Spencer is protesting at restrictions on land clearing, imposed as greenhouse gas abatement measures.

He has vowed to maintain his protest until the Government agrees to hold a royal commission.

Graham Spencer said his brother owed "more than a million dollars" to a family member after being given a loan to prevent the bank seizing his farm. "Peter doesn't owe money to the bank, but to the family," Graham Spencer said.

"One of the family members lent him the money, and I think the arrangement was he would make the interest payments."

Graham Spencer said the family had made numerous attempts to accommodate Peter Spencer's failure to pay the debt, which had been outstanding for some years.

But in October the family had been forced to seek a writ of possession that could force the sale of the property.

"It's nothing to do with the banks - it's a straight family dispute, and that's where it should stay. Let the family sort this out," Graham Spencer said.

Read more about Peter Spencer at The Australian.