MNsure still hasn't sent more than 21,000 tax forms to people who bought coverage through the state's health insurance exchange last year.

The forms were due Feb. 1, but MNsure officials said nearly two weeks ago that most were late because of delays with a new automated process for generating the documents.

On Feb. 17, the MNsure chief executive said the goal was to send all forms by Monday, but the job on Tuesday was only 54 percent done.

"The remainder will be sent out as quickly as possible," spokesman Shane Delaney said in a statement. "We're getting down to some very complicated cases, and that is causing our IT staff to perform additional review on many of these to make sure the information on the form is accurate."

People need the documents before filing their taxes, which are due April 18.

Minnesota launched the MNsure exchange in late 2013 to implement the federal Affordable Care Act, which makes tax credits available to individuals and families that buy private health insurance policies through a government-run exchange.

Based on income projections, MNsure shoppers access tax credits to discount premiums as they pay for coverage during the year. At tax time the following year, people need the MNsure forms to reconcile the subsidies they received with what they should have collected based on their actual income.

In addition, people who qualify for tax credits can defer the benefit until tax time — a circumstance where taxpayers this winter might be eager to get paperwork and file returns as quickly as possible.

Delaney said another batch of forms is scheduled to go out this week. He did not offer a specific timeline for when the job would be done.

"We are keenly aware of the tax filing deadline," Delaney said. "We will definitely have them out before then."

MNsure officials said the new automated process for generating forms will benefit taxpayers in the long run, but some have been expressing frustration on social media about this year's experience.

As of March 6 last year, MNsure had sent more than 33,000 forms, and had another 1,300 documents to deliver. As of Tuesday, 25,156 forms had been mailed, Delaney said, with another 21,675 forms yet to be sent.

Like last year, MNsure has delayed sending many forms to ensure accuracy. Forms are more complicated when people have coverage for only part of the year, Delaney said, or when changes in income or household composition change eligibility for tax credits.

In the end, the error rate on forms during the 2015 tax season was less than 3 percent. That was better than for the federal HealthCare.gov exchange, which in February 2015 said that about 20 percent of filers who got tax credits through the website — roughly 800,000 people — would be receiving corrected forms.

Christopher Snowbeck • 612-673-4744

Twitter: @chrissnowbeck