Prime Minister Malcolm Turnbull and Queensland Premier Annastacia Palaszczuk will be among the dignitaries gathering in Kingaroy to farewell Lady Florence Bejelke-Petersen.
A state funeral will be held on Thursday for the former Queensland senator and wife of Premier Sir Joh Bjelke-Petersen, in her home town at the Kingaroy Town Hall.
It is the same venue that hosted the state funeral for Sir Joh, Queensland's longest-serving premier, in 2005.
Lady Bjelke-Petersen died at the age of 97 on December 20 following complications from a fall she suffered weeks earlier.
While best known for being the wife of Sir Joh and for her pumpkin scones, Lady Flo - as she was affectionately known - served as a Nationals senator from 1981 to 1993, and served on a number of Parliamentary Senate Committees.
One of her final wishes was for her controversial husband's tarnished political reputation to be restored, after he was dumped as leader of the Nationals in 1987 after almost 20 years in office amid a corruption scandal.
In 1991, the 80-year-old was charged with perjury arising from his evidence to the Fitzgerald Royal Commission, but a jury was unable to reach a verdict.
Mr Turnbull, Deputy Prime Minister Barnaby Joyce and Ms Palaszczuk are expected to speak at the service.