"The plan will cover a three-month period, whereby about 800,000 illegal Afghan workers will be screened and dealt with," the ministry's general director of foreign nationals employment, Mohammad Hassan Salehi Maram, was quoted as saying.
"Currently, the number of Afghan residents in Iran is three million, out of whom about 1.3 million are working in various places," he said.
Temporary six-month work permits could be issued for foreign workers, including the Afghans, he explained, adding that the permits would only apply to three sectors of "brick-burning plants, construction and agriculture."
"After three months, the (tracking) plan will be repeated until no more illegal foreign nationals remain in the country," Salehi Maram added.
The interior ministry's figures have put the number of registered Afghan nationals at more than one million -- up 8.5 percent from February.
According to interior ministry estimates, some 950,000 more are reported to be living in the country illegally.
But some unofficial reports said only a few thousand illegal Afghans have work a permit.
The drive will see employers rewarded if they lay off unregistered workers and possibly jailed if they fail to do so.
"The employers who do not report their illegal Afghan workers will be fined and jailed," the student news agency ISNA quoted Salehi Maram as saying.
"On the other hand, if they are replaced with Iranian unemployment pensioners, the employers will be given loans and exempted from insurance fees for the new workers for four years," he added.
The move is to reinforce the constitution, which bans foreign nationals from being employed in Iran without work permits under the labour law.

Copyright AFP (Agence France-Presse), 2006