Their #NoAlPadron platform instructs citizens on how to get involved in the amparo lawsuit, which is specifically brought against authorities suspected of violating constitutional rights.
The group set a deadline of 31 May for citizens and other groups to join their action. Mexico's mid-term elections are scheduled for 6 June and could see President Andres Manuel Lopez Obrador (AMLO) achieving a large enough majority to push through the bill.
The coalition includes 14 organisations, including Red en Defensa de los Derechos Digitales (R3D), Article 19, PODER and Social Tic, which has drawn criticism from AMLO in the past.
Access Partnership policy manager, Yamel Sarquis, said: "As the weeks pass and the mid-term elections near, pressure continues to mount for President Andres Manuel Lopez Obrador to withdraw the national registry of mobile phone users bill.
"The backlash sets a strong precedent and denotes the increased public awareness around data protection debates in Mexico. More broadly, it also adds tension to the feud between AMLO and autonomous institutions. And the big question remains—will Lopez Obrador double down, or will he cave?"
Sarquis explained: "The latter approach comes with a caveat—if AMLO achieves a two thirds supermajority, his party would have a blank check to modify the constitution at will."
The National Register of Mobile Telephone Users (PNUTM) is intended to tackle crime, particularly kidnap and extortion, which authorities have said is enabled by criminals being able to obtain mobile phone lines anonymously. It would be established by amending the Federal Law on Telecommunications and Broadcasting.
The idea was first introduced in 2009, when then National Registry of Telecommunications Users (RENAUT) was launched, and rules were scheduled to come into play the following April. However, the scheme was suspended in 2012 and the database decommissioned, with GSMA later noting "the significant financial investment by all the operators and the authorities was written of".
GSMA has previously shared its concerns with Capacity and PNUTM has faced opposition from the National Institute for Transparency, Access to Information and Protection of Personal Data (INAI), the Federal Telecommunications Institute (IFT) and the National Commission on Human Rights (CNDH), among others.
The bill was approved by the lower house in February and by the senate on 13 April, but at 54 votes in favour, 49 against and 10 abstentions in the latest hearing, the backing was far from unanimous. Then, in April, a judge blocked part of the necessary amendment to the Federal Telecommunications Law.
At the time, Judge Juan Pablo Gomez Fierro was quoted by local media as saying the registry did not "positively influence" the state's public security activities.
