In an amendment to the northern Italian region's rules governing tourism, the party wants to ban hotels from being used to house people “who have entered Italy illegally”.
Hoteliers caught flouting the rule risk losing their licence for between six months and a year, as well as a fine of between €5,000 and €10,000, La Repubblica reported.
The proposal comes a week after Italy's government called on regional leaders to find accommodation for a further 20,000 asylum seekers.
Signed by Massimiliano Romeo, the party's whip in the Lombardy council, his deputy Fabio Rolfi and councillor Pietro Foroni, the measure stipulates that hotels will only be able to host those who have “entered Italy legally” or ”migrants who have a valid residency permit” and who have undergone the identification and verification process towards obtaining “real refugee status”.
For those without refugee status, the party said their accommodation should be guaranteed by the state through "special reception facilities", or through cooperatives and companies that work specifically to support people in need.
The proposal comes a few months after Lombardy's president, Roberto Maroni, who founded the Northern League, told mayors and other officials in the region to refuse to accept any more migrants.
Matteo Salvini, the party's leader, has also denounced those who have had “to wait for landings at Lampedusa” in order to fill their hotel rooms.
Meanwhile, EU ministers on Monday failed to reach unanimous agreement on a plan for binding quotas to relocate 120,000 refugees and take the strain off Greece, Italy and Hungary.
Refugee care costs the Italian government up to €800 million per year, as it offers private individuals, companies and non-profit organizations up to €35 a day per person to host them.
From that figure, hosts must give a daily pocket money allowance of €2.50 each.
More than 115,544 people have been rescued by Italian authorities from the Mediterranean so far this year.