Mr Spencer is now on day 43 of his strike, insisting he will not come down from a weather tower until he can speak to Prime Minister, Kevin Rudd.

Mr Spencer has accused the Federal Government of "carbon theft", which he alleges as a result of land clearing laws.

He said the laws were imposed as a result of a deal done by the States with the Howard Government so it could meet its Kyoto targets.

He said farmers should be compensated for the near 80 million tonnes of carbon sequestered as a result of land clearing restrictions.

At a $25 a tonne market price for carbon, farmers could be owed some $2 billion if that carbon was actually recognised as a property right.

Queensland Nationals Senator, Barnaby Joyce addressed the crowd and while urging them to keep up the fight on land rights, he also made a plea for Mr Spencer to end his hunger strike before he seriously harmed himself.

NSW Nationals MP, Kevin Humphries also spoke to the crowd, and said Mr Spencer represented the thousands of farming families which have been affected by the onerous land clearing laws first enacted by the Carr Government in 1995.

Mr Spencer's children thanked marchers for their support, and told of their hope that they would see their father come down from his strike before flying back to their homes next week.

A number of farmers in the crowd travelled more than 10 hours to attend today's rally – a large contingent from the native veg hot spots of Nyngan and Tottenham which have battled with the Government to ease its restrictions for more than a decade.

Many will visit Mr Spencer at his property this afternoon.

The Prime Minister has so far refused to meet with Mr Spencer, and said he should pursue his concerns in the courts.

Mr Spencer has so far had close to 200 court appearances on the issue, but the matter has stalled at the High Court without a hearing.