MEXICO CITY, Aug. 22 (Xinhua) -- Cancelling the construction of a new international airport in Mexico would have a negative impact on tourism and halt future investment, credit rating agency Moody's said on Wednesday.

The controversial project, under construction but riddled with problems and delays, is one of the largest in the world. It is driving Mexico's non-residential real estate investment, which has been declining since 2016, Moody's said in a report.

If the project is cancelled, it would directly affect investment and employment, and result in a lost opportunity for Mexico in terms of competitiveness, Moody's said, adding it could also derail the upswing in Mexico's tourism.

In 2017, Mexico climbed to sixth place in the ranking of the world's most visited countries, with 39.3 million visitors, according to the World Tourism Organization.

Mexican President-elect Andres Manuel Lopez Obrador has proposed holding a referendum on whether to continue or scrap the controversial project, mainly due to the corruption and irregularities involved in it.

One-third of it has been completed, with 5.2 billion U.S. dollars already invested, according to data from Moody's, which put the total cost at 15.7 billion U.S. dollars.

If construction is continued, the airport is expected to be operational by November 2020.