Ian Lavery said polling on shadow cabinet members was carried out in Manchester ahead of the upcoming mayoral election and such research was not “uncommon”.
Rising party stars including Angela Rayner and Rebecca Long-Bailey were said to have been assessed for popularity as part of internal “succession planning”, according to The Sunday Times.
Mr Lavery told the Pienaar’s Politics programme on BBC Radio 5 live: “The reality about polls is that it’s not uncommon for any political party to conduct these political polls in order to establish a clear reasoning, understand the various different views in a particular point in time.
“We were doing this in Manchester, we have got the Manchester mayoralty coming up very soon. We wanted to establish the views, listen to what people have had to say so we can get the right message across.
“I think they are fantastic candidates. I think we have got lots of quality in the Labour Party and it’s not just the two that’s been mentioned.
“There’s plenty of leaders to pick from if and when Jeremy decides, of his own volition, that it’s not for him at the election. That isn’t the case at this point in time.”
The Wansbeck MP said he was “pretty confident” Labour could hold its seats in Copeland and Stoke-on-Trent Central but strategy would be reviewed if there were any “hiccups”.
Shadow attorney general Shami Chakrabarti told ITV’s Peston on Sunday that if Labour lost the forthcoming by-elections in Stoke and Cumbria, Mr Corbyn would remain leader.
Earlier, Labour deputy leader Tom Watson urged Mr Corbyn to improve his popularity ratings.
The Sunday Times also suggested leaked documents gave a scathing assessment of the embattled Labour leader, who was found to be “boring” and “fed up” by focus groups.
It also cited polling in the leaked document that rated veteran left-winger Mr Corbyn as the least popular of all current party leaders, including Ukip’s Paul Nuttall, who is standing in the upcoming Stoke-on-Trent central by-election.
Speaking on the BBC’s The Andrew Marr Show, Mr Watson said: “It wasn’t road testing leadership candidates. There were a range of shadow cabinet members that were so-called road tested, this is what we do in our normal run of political consultations.
“I’m just slightly relieved they weren’t road testing me on the document that was leaked to the newspaper.”
When asked about a recent YouGov poll that suggested Mr Corbyn’s favourability ratings were plummeting, Mr Watson added: “This is not the time for a leadership election. He got a second mandate from our members last year, he is now the established leader of the Labour Party.
“He has to explain those and he has to improve on them and he’s well aware of that.”
Mr Watson also questioned the timing of the resignation of Clive Lewis as not “particularly helpful” but welcomed the former shadow business secretary’s denial of rumours he was mounting a bid to topple Mr Corbyn.
The Norwich MP was the most high-profile rebel to resign from Mr Corbyn’s top team ahead of defying the leader on a three-line whip by voting against triggering Article 50.
The Labour leader was forced to reshuffle his top team after a number of members quit ahead of the vote.