But the Transport Workers Union won't rule out disrupting bread supplies if owners of Tip Top Bread don't sit down and negotiate a fairer return for delivery drivers.

In a show of defiance owner/drivers finishing their shifts this morning met in front of George Weston Foods depot in Griffith to call on the owner of Tip Top Bread to freeze any changes to contracts and begin negotiating.

Owner/driver Aleni Otuhouma of Isabella Plains, who is half way through repaying $120,000 on his vehicle, says he is losing $3500 a week and being asked to deliver more bread.

The TWU says Canberra has about 14 distributors like Mr Otuhouma, and since two left their runs the remainder have been asked to pick up extra work, for reduced incomes.

Mr Otuhouma, now a father-of-two since the arrival last week of his son, is working 80 hours a week and paying off a mortgage.

He says this is another case of a big business running down smaller businesses. "Something has got to give," he said.

In a statement Tip Top says fewer customer drops caused the changes to contracts.

"Tip Top has provided all individual distributors with reasonable notice in line with their existing contracts, and is now actively engaged in discussion with these distributors and working to resolve any concerns regarding individual delivery runs in a timely manner."

TWU Canberra sub-branch secretary Klaus Pinkas says the drivers are paid per loaf of bread under a complicated system that varies on the variety of bread and kilometres they travel.

"They are being asked to do more for less pay. The big issue is the rate is not sustainable.

He says this "crazy" attempt to force reduced contracts on distributors will be felt in Cooma, Bega, Batemans Bay, Young and Wagga as well as Canberra.

"Runs have been reduced and payments slashed with no consultation and no regard to personal circumstances of the contractors, including some who have delivered bread for the company for over 20 years," Mr Pinkas said.