Federal NDP Leader Jagmeet Singh says he will continue to stand as his party's candidate in the B.C. riding of Burnaby South, despite news this week that the Liberal MP in his home riding of Brampton is leaving politics.

"I made it clear my decision to run in Burnaby South and I continue to remain clear on that decision," he told reporters on Friday.

Singh's statement comes hours after Brampton East Liberal MP Raj Grewal announced his decision to quit federal politics, citing "personal and medical reasons."

Singh, who held the Brampton riding at the provincial level until late 2017, had previously said he wanted to run in the riding at the federal level. In early August, however, he announced he would be the NDP's candidate in Burnaby South.

A recent poll by Mainstreet Research suggested Singh was running third in the riding, echoing internal numbers both Liberal and NDP MPs have murmured about in the halls of Parliament.

There is a feeling among Liberal ranks that they benefit from Singh remaining the leader of an anemic NDP and don't want to see him fail before the next election.

Under Singh's tenure, a handful of NDP MPs have said they won't run in the 2019 election or have already stepped aside.

The party sits at 15.8 per cent support in CBC's Poll Tracker, an aggregation of all publicly available polling data. That number would put it on track for its worst performance since 2004.

Nevertheless, earlier this week, the Liberals confirmed they would not extend a "leader's courtesy" and would put up a candidate to compete against Singh in Burnaby South. The byelection is to replace former NDP MP Kennedy Stewart, who stepped down for a successful run to be mayor of Vancouver.

On Wednesday, several media outlets reported on an unnamed Liberal official confirming the prime minister intends to call the Burnaby South byelection early in the new year, with the date to be set for some point in February.

Grewal announced his decision to step down in Brampton East the next day. On Friday, Singh reiterated his decision to run in B.C.