The Council of Canadians has asked Elections Canada to turn over more information to the Federal Court about its probe into the strange phone calls, including the nature of voter complaints.
But Conservative party lawyer Arthur Hamilton says the deadline has passed to file new evidence.
The council is backing applications asking the court to review the May 2011 election results in seven ridings where Conservative MPs narrowly won their seats.
The council alleges misleading or harassing phone calls in those ridings kept some people from voting and may have affected the outcomes.
The law lets voters legally challenge the results in their ridings.
If a judge finds anything that would have changed the outcome, new byelections can be ordered.