Duceppe, however, says he's followed the rules in such matters.
La Presse says Gilbert Gardner was hired in 2004 to work at the Bloc's headquarters in Montreal and earned a salary of more than $100,000 in the final years of his term.
NDP MP Joe Comartin, vice-president of a parliamentary committee on procedure and house affairs, says the payments would be a violation of parliamentary rules, since the House of Commons funds were meant for activities related to Parliament, not for partisan ones.
He says he's seeking legal advice to determine whether a case can be made against Duceppe to force the former Bloc leader to pay back the cash.
Duceppe told La Presse that Gardner was paid by his Ottawa cabinet but said that he followed the rules, adding that he consulted parliamentary experts to ensure that was the case.
The allegations come amid rumours that Duceppe is working to replace Pauline Marois as head of the provincial Parti Quebecois.
The Bloc's current leader Daniel Paille issued a statement Saturday saying he wouldn't comment on the report.
Duceppe, who stepped down as leader after the Bloc's disastrous showing in the election last May, hasn't yet returned an interview request from The Canadian Press.
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