PGA Tour commissioner Jay Monahan reportedly faced calls to resign at a heated players' meeting following the announcement of a shock merger with LIV Golf.

Monahan was accused of hypocrisy after announcing that the US-based PGA Tour and Europe's DP World Tour had agreed a tie-up with the Saudi-backed rebel circuit in a bid to end golf's civil war.

LIV Golf launched last year with eight events, luring top talent with record $25-million purses and money guarantees, bankrolled by Saudi Arabia's Public Investment Fund.

Monahan, who has railed against LIV since its inception, attended a tense meeting with players on Tuesday ahead of the Canadian Open in Toronto.

US media reported that furious players — who had been kept in the dark about the merger until the news broke — challenged Monahan over the bombshell announcement.

In a media conference call later Tuesday, Monahan acknowledged that criticism directed at him was inevitable, saying he understood being branded a "hypocrite".

The Golf Channel reported that former three-time PGA Tour winner Johnson Wagner had access to an audio feed of the meeting, which he described as "contentious", saying "a lot of players are unhappy".

"There were many moments where certain players were calling for new leadership of the PGA Tour and even got a couple of standing ovations," he told the channel.

He added: "As we step away from this and see it unfold in the coming weeks I think we'll get more clarity but there was a lot of anger in that room from players, feeling like they can't trust what the leadership of the PGA says any more."

Wagner said the future pathway for LIV players to return to the PGA Tour was unclear.

And he said it was difficult to predict the shape of tournaments.

LIV events are played over 54 holes rather than the traditional 72-hole format and use "shotgun" starts, with golfers starting at the same time on different holes.

"I don't think he (Monahan) has the answers to that yet," he said. "I think we're in the infancy of this whole thing so there was no real discussion of what it's going to look like."

Monahan insisted that his staunch defence of the tour over the past year had been in good faith, but that "circumstances do change."

He defended the cloak-and-dagger nature of the merger talks with LIV that led to Tuesday's announcement.

"Given the complexity of what we were dealing with, it's not uncommon that the circle of information is very tight," Monahan added.

Rory McIlroy, one of the most vocal opponents of LIV among the PGA Tour's players, is playing at the Canadian Open this week and is due to speak to reporters later on Wednesday.