He said minister-delegate for Administration, Victor Paul Dobre, has also resigned.
Rus and Dobre resigned amid uncertainty over the number of eligible voters in Romania, which is essential in determining the outcome of the July 29 impeachment referendum targeting suspended President Traian Basescu.
The Constitutional Court is expected to rule on the outcome of the referendum on August 31. The Court has asked to analyze voter lists, after it received discrepant data regarding the number of voters from the Interior Ministry.
The impeachment referendum required a voter turnout of more than 50% of eligible voters to be validated. The Central Electoral Bureau announced the voter turnout was 46.24%, of which an overwhelming 87.52% voted to impeach the head of state.