CAMHS statistics published last week have shown that across Scotland 10,452 children and young people were waiting on treatment at the end of December 2021, including 1,887 in Lanarkshire.
A total of 68 per cent of patients in NHS Lanarkshire waited longer than the 18-week target time to begin treatment.
Nationally, 23 per cent of CAHMS referrals were rejected in the quarter ending December 2021, but in NHS Lanarkshire 32.6 per cent were rejected.
Mr Griffin, who is List MSP for Central Scotland, said: “Young people have been hit hard by the pandemic and, as a result, we know that many young people are dealing with mental health issues.
"Despite this, the SNP government has failed to properly re-mobilise CAMHS services.
"This is especially evident in Lanarkshire, with almost one in three CAMHS referrals being rejected and a staggering 68 per cent of patients waiting longer than the target time to begin treatment.
"This has to end. Minister for Mental Wellbeing Kevin Stewart must take action now to sort this situation out.
When asked for comment, Mr Stewart said: "While too many young people have had to wait too long for treatment it is important to highlight that the number of people receiving support from CAMHS within 18 weeks, (3195) is the second highest on record.
“We have specifically invested £4.25million this year to help Boards tackle backlogs in CAMHS care and it is encouraging to see they have targeted this resource to increase activity to record levels this last quarter.
"This has been made possible by the hard work of NHS staff and sustained growth in the CAMHS workforce. Under this Government, since 2007 CAMHS staffing has increased by 83.4% and we continue to create posts.
"Long waits for treatment are unacceptable and we remain committed to meet the standard that 90% of patients begin treatment within 18 weeks of referral.”