A Gisborne forestry contractor is calling for Immigration Minister Iain Lees-Galloway to resign over delays to the migrant work visa process.

Jason Koia employs 24 fulltime workers, 10 of whom are from overseas.

But he says he still needs up to 40 more planters this season. He submitted migrant visas back in April, but delays in processing applications has affected his business and is costing the industry hundreds of thousands of dollars.

Koia told Mike Hosking that they are so far behind they need 15 people immediately.

He says the delays are getting worse.

"Unfortunately, the planting season's going to expand again. We're going to try and pre-empt everything sic months in advance and hopefully we can time it right."

He says two years ago, applications took two weeks to process - but now it's closer to four months.

Koia wants there to be a more streamlined process.

"Don't get me wrong, I'm all for Kiwis first, but if we can't find them first you've got to find someone second, because if someone doesn't put trees in the ground, you're not going to create jobs for Kiwis further on down the line."