Figures published this morning show the proportion of patients with suspected cancer starting treatment within two months of diagnosis has hit its lowest rate for over five years.
The Welsh Government target is for 95% of patients to begin treatment within 62 days, but the figure for January – March 2013 is just 83.6%.
The 95% target has not been met once since 2008.
Darren Millar AM, Shadow Minister for Health, said, "The proportion of cancer patients starting treatment promptly is at its lowest rate for over five years.
"The Welsh Labour Government’s target of 95% of patients starting treatment within 62 days has not been met once since Carwyn Jones became First Minister.
"Month after month Welsh Labour Ministers give out feeble reasons as to why cancer waiting times are getting worse and persistently deny that their £800million cuts to the Welsh NHS budget are to blame.
"When a patient receives the devastating news that they have suspected cancer, rapid progression to treatment is vital, but unfortunately Labour’s NHS cuts are constraining capacity and putting additional pressure on already stretched staff.
"It is time for Carwyn Jones’ Labour Government to revisit its record-breaking cuts to the NHS budget and ensure that cancer services in Wales are properly funded so the NHS can help more patients to live through and recover from cancer."