Their statement came after Venezuela's opposition rejected the authorities' assertion that Maduro -- who has led the country since 2013 - won with 51 percent of the votes in Sunday's election.

"We call on relevant representatives to publish the detailed electoral results in full transparency and we ask electoral representatives to immediately share all information with the opposition and independent observers," the ministers said in a statement.

"Independent domestic and international observers' reports have raised serious concerns about the announced results...," they added, citing "irregularities and lack of transparency in the final tabulation of the votes".

They expressed "solidarity" with the population of Venezuela and called for "maximum restraint in the country and for a peaceful, democratic and Venezuelan-led solution".

The G7 nations are the United States, the United Kingdom, Canada, France, Germany, Japan and Italy.