An extension of the registration period to vote in the Liberal leadership race that had been requested by the Justin Trudeau camp will be granted, Liberal sources say.

The decision is expected to be formally announced on Wednesday afternoon.

While Mr. Trudeau had asked for an extra week beyond the Thursday deadline to make sure most of his supporters were on the voters' lists, the Liberals say they will give as much time as they possibly can – likely even more than the week that had been requested.

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That could mean the seven remaining candidates will have until just a couple of days before the voting begins on April 6 to get their supporters registered.

Mr. Trudeau's campaign workers wrote to the Liberal party this week to ask for the extension, saying some of their supporters had yet to receive the registration forms by mail and others were being prevented from registering by computer glitches.

As of the start of this week, less than a third of the party's nearly 300,000 signed-up supporters and members had taken the supplementary step of registering to vote, which is required before they can cast a ballot.

The decision by Liberal brass to accede to Mr. Trudeau's request will undoubtedly anger workers at other campaigns, especially that of British Columbia MP Joyce Murray, who argued that no extension is necessary and that all candidates have been aware of the rules and the deadlines since last fall.

Because Mr. Trudeau has so many more supporters than the others, the extension is likely to work in his favour. But Liberal officials say they want to give all of their supporters a chance to vote and do not want to alienate people, especially those who have just recently taken an interest in the party as a result of the leadership campaign and Mr. Trudeau's own personal popularity.