Are you true left handed or just cast left handed?
I'm left handed and cast left handed. I net with my right hand. On those rare occasions where I need a net, I do as Hugh said and just use the net in my right hand.
If you are left handed, you have a significant advantage over right handed people and here is what it is. The world is set up for a right handed person. For that reason, a left handed person has to use his/her right hand far more than right handed people have to use their left hand.
You probably already have far more manual dexterity and hand/eye coordination with your right hand than most right handed people have with their left hands.