Liberal Leader Yvonne Jones wants legislatures across the country to support a move to lowering the recommened age of breast cancer screening to 40. (CBC)

Newfoundland and Labrador's Liberal leader spoke out Wednesday in favour of breast cancer screening for women in their 40s.

Yvonne Jones, who took a leave of absence as Opposition leader in August to fight her own cancer diagnosis, said she is leading a national campaign to lower recommended ages for breast cancer screening.

Many experts recommend annual mammograms for women once they turn 50. The recommendation is made in part to avoid unnecessary medical procedures and costs.

But Jones said cancer is changing, and the recommendation should change.

"More and more women my age are getting breast cancer," said Jones, 42, who asked to be tested in the wake of last year's Cameron inquiry into errors with hormone receptor tests given to diagnosed cancer patients.

"Many will take too long to get screened and therefore not receive the early diagnosis that gives them the best chance at beating it," Jones told reporters, during her first news conference since revealing her diagnosis.

Jones, who will start the next round of chemotherapy on Thursday, said she has raised the issue with Premier Danny Williams, and intends to introduce a private member's bill in the house of assembly this fall.

"The campaign involves convincing every legislature across the country to expand their provincial breast screening program to women as young as age 40," she said.

Jones said Newfoundland and Labrador can accommodate handling women in their 40s.