The Support Sleeve provides collapse-resistance and ensures long-term reliable pack-off and suspension of HDPE tubing. When HDPE tubing is used as a velocity string, the tubing is run to depth and hung-off in a Select Coiled Tubing Hanger and pack-off assembly. The HDPE coiled tubing is supported by positioning the smooth section of the Support Sleeve adjacent to the packing element in the hanger. The hanger element may now be fully energized without risk of collapsing the tubing.