Mexico's Green Party (Partido Verde Ecologista de México, or PVEM) was penalized again this week as calls for the group's deregistration grew. The National Electoral Institute fined PVEM about 322 million pesos, or about $21 million, Wednesday for advertisements the group paid for illegally, CNN reported. The decision came as a petition demanding authorities withdraw PVEM's registration surpassed 150,000 signatures.

"The fines to be imposed on the Green Party are insufficient and ineffective," the petition's authors wrote in Spanish. "It is time that citizens demand that the law is enforced and that the authorities do their job."

But when the topic came up Wednesday during a meeting of the congressional Permanent Commission, politicians shut it down. Senators and deputies affiliated with PVEM and the ruling Institutional Revolutionary Party (PRI) voted against discussing opposition Sen. Armando Ríos Piter's proposal that the party be disqualified from next month's congressional elections, Aristegui Noticias reported.

Ríos Piter and the petitioners argued that PVEM continually violated electoral regulations. In this election cycle, the small party has been disciplined for giving out free movie tickets, gift cards and calendars made -- ironically -- from toxic materials, Telesur reported. "To request the cancellation of the PVEM is the least we can do," Ríos Piter said in Spanish. "This impunity is now a reflection of the massive corruption that exists in our electoral system."

PVEM has fired back, saying they haven't committed any irregularities and are only being prosecuted because other parties have pressured the electoral authorities to change the rules, journalist Gustavo Rentería reported. The party's spokesman, Charles Bridge, told reporters it intended to file a complaint against Mexico's government in the Inter-American Commission on Human Rights, Excelsior reported.

PVEM is one of 10 parties campaigning ahead of Mexico's legislative election set for June 7.