A former politician says there's questions about the Green Party's leadership and vetting processes

MP Darleen Tana's been stood down after allegations of migrant exploitation at E Cycles NZ, a business owned by her husband.

The party was made aware of complaints to the Employment Relations Authority in early February -- and yesterday found she may have had prior knowledge of the allegations.

An independent lawyer will investigate what she knew.

Former Minister Peter Dunne says there's unanswered questions about what Tana knew when she was selected.

He says Chloe Swarbrick says it's incredibly serious, but the party seems slow to respond, so there's questions about its leadership and management.