The lineup for Australia's gruelling Sydney to Hobart bluewater classic this year includes a wooden boat built in 1904, the oldest vessel ever to compete in the race.

A total of 164 yachts are expected at the start line for the milestone 75th Sydney-Hobart race on December 26, making it the biggest fleet in 25 years, officials announced on Wednesday.

Katwinchar, a 10-metre ketch built in 1904, is one of several older wooden vessels taking part in the often brutal 628-nautical mile (1,163-kilometre) slog across the Tasman Sea.

Australian boat-builder Bill Barry-Cotter said his father had part-owned Katwinchar for a few years in the 1960s until it "basically disappeared".

"I started advertising for it 10 or 12 years ago and got nothing, then suddenly somebody rang me up and said it was on (e-commerce site) Gumtree," he said.

"So I went down and got the boat, it was in a very bad shape."

Barry-Cotter has spent years restoring the boat to its former glory so he could enter it into this year's historic event.

Katwinchar also competed in the Sydney-Hobart in 1951 after being sailed across from Britain for the race, and will this year be skippered by Barry-Cotter's brother, Kendall.

Supermaxi Wild Oats XI won a record ninth line honours in 2018's ocean race after a thrilling battle between four supermaxis that exchanged the lead several times.

Fierce competition is expected when the yacht defends its title next month.