Chief Minister Andrew Barr will make the election promise when he addresses the Labor Party conference on Saturday.

He said the centres would make it easier for more Canberrans to "access even better care".

The government opened two walk-in centres in Belconnen and Tuggeranong in 2014.

The Belconnen centre had more than 16,000 attendances last financial year while Tuggeranong had just over 17,500.

"The nurse-led walk-in centres provide free one-off advice and treatment for people with minor illness and injury. This ensures that all Canberrans can get the health support they need," Mr Barr said in a statement.

"The centres also take pressure off other areas of the health system."

In what is likely to be one of many election pitches to come during the next three months, Mr Barr said there was "only one party in this city that cares about providing better health services for all Canberrans, not just those that can afford it".

"This is part of my government's promise to the people of Canberra – that you can only trust a Labor Government to ensure you have access to the health services you need," he said.

Mr Barr said the government had invested $1.6 billion this year on health services in the ACT and was spending $212 million on a teaching hospital at the University of Canberra and $139 million on more nurses and doctors.

"While Liberal Governments have been ripping millions of dollars out of our hospitals, despite promising not to, my government has been investing more to provide better health services right around the territory," he said.