Prime Minister Justin Trudeau’s government was “insufficiently transparent” about foreign interference in Canadian politics and sometimes took “too long to act’’ against attempts to meddle in the country’s past two general elections by foreign powers including China and India, a government commission said on Tuesday.

“Trust in Canada’s democratic institutions has been shaken, and it is imperative to restore it,’’ the commission said in its final report, which summarized 18 months of hearings, testimony and examination of classified intelligence documents.

The government’s efforts to rebuild trust have been “piecemeal and underwhelming,’’ said Marie-Josée Hogue, a Court of Appeal justice from Quebec, who led the commission.

The final report included 51 recommendations by the commission to strengthen Canada’s electoral system, ranging from stricter rules for the country’s political parties and third-party financing to better sharing of intelligence and oversight of disinformation during campaigns.

Justice Hogue said about half the recommendations “should be implemented promptly, perhaps even before the next election.’’

There Trudeau government had immediate response to the report.

But the recent announcement by Mr. Trudeau, who is deeply unpopular, that he will step down as Liberal Party leader and prime minister makes it unlikely that the commission’s recommendations can be put in place before upcoming elections, experts said. Members of the Liberal Party are expected to elect Mr. Trudeau’s successor by early March, and a general election is likely to take place a couple of months later.