Diario de Cuyo quotes Chilean mayor of Vicuña, saying "based on the information he has", "former Argentine president Mauricio Macri had asked Sebastián Piñera (then-president of Chile) to stall the Agua Negra Tunnel project"."Macri did not want a project which would benefit the San Juan region, but rather preferred to channel resources to the Mendoza region where he had more political returns".

If ever constructed, the Agua Negra Tunnel will be an important part of the much larger Bioceanic Corridor project. The 14 kilometer long tunnel would connect Argentina and Chile through the Los Andes massif.

The IDB (Inter American Development Bank) had made US$ 1.5 Billion available for each country for the construction of the Agua Negra Tunnel.  The government of Chile had decided to renounce the loan while Argentina took it. But if it is a tunnel between two countries, it takes two to tango. Argentina cannot build the tunnel on its own. At the time, there was presidential elections in Chile and none of the candidates considered the tunnel a priority, including the the then-president  Sebastián Piñera, the person who rejected the loan.

Left with US$ 1.5 Billion loan, Argentina had been looking around for projects to assign the parts of the loan.

Here the allegations of the mayor of Vicuña (in Spanish)

https://www.diariodecuyo.com.ar/politica/Tunel-alcalde-chileno-dijo-que-Macri-le-pidio-a-Pinera-no-avanzar-para-beneficiar-a-Mendoza-20220225-0076.html