820 girls and women trafficked to the Middle East in 2016, with the promise of work amid biting economic crisis.
Under a new proposal migrants would have to earn a minimum of NZ$49,000 to be considered skilled workers.
Selling migrants from West Africa is becoming a trend among smugglers in Libya.
The four-year work visa is to be replaced with two new temporary visas that require better English-language and work skills.
More than 5,000 migrants rescued but Italian coastguard reports at least 20 deaths from drowning.
'The sea continues to be a graveyard,' said Médecins Sans Frontières.
Roberto Beristain was detained on 6 February after he went in for a routine check with ICE officials.