"This is one of the biggest corruption scandals not only in our country but in the whole region," Zaev, head of the main opposition SDSM party, told a press conference.
Zaev accused Gruevski of awarding the construction of two highway sections to Chinese firms without a tender.
The total value of works carried out on the western Kicevo-Ohrid highway and the eastern Miladinovci-Stip motorway was estimated at 570 million euros, Zaev said.
Recent bitter exchanges between the government and the opposition have pushed the former Yugoslav republic into a deep political crisis this year.
In January, the government filed a complaint against Zaev and several other people for espionage and violence against officials.
The opposition leader rejected the allegations and in turn accused the government of wiretapping at least 20,000 people, including politicians, journalists and religious leaders.
Earlier this month, Zaev called on the prime minister to resign, form an interim government and organise "fair and democratic" early elections.
European Union officials have expressed concern over the "deteriorated political dialogue" in Macedonia, and called for a thorough investigation.
Meanwhile, local media reported that government and opposition representatives were expected to hold EU-mediated talks on Monday in Brussels to address the crisis.
The Socialists have been boycotting the Macedonian parliament for almost a year, alleging electoral fraud during early polls held in April 2014.
The next parliamentary elections are due in 2018.
The Balkan country obtained EU candidate status in 2005, but is yet to begin accession talks.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Access to Exclusive Premium Stories
Over 30 subscriber-only stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app