Googling around I found this page of somebody who saw Sirius in daylight with the NE in Zimbabwe. There Sirius passes overhead as it is on the latitude 17šS same as Cairns.
http://adsabs.harvard.edu/full/1984JBAA...94..221H
I did manage it one in March 1986 from Canberra in late afternoon. Looked up Sirius with an 80mm scope (which I still have but with renewed optics) and looking along the tube and I saw a very pale dot on the limit of visibility .... Yes !!!
Later attempts (from South Africa in Mar 1997 and '98) failed. Here in NL Sirius is too low in the sky.
Did somebody succeed to see Sirius with NE in daylight ?
Note: daylight == sun above horizon even when a few degrees.
NE: normal eyeglasses / contact lenses are considered as Naked Eye as long no light collecting optical device such as a telescope is used.