Julie Bishop’s attempt to become leader of the federal Liberal party during last week’s leadership spill was deliberately thwarted by her colleagues.

WhatsApp messages leaked to the ABC’s Insiders program show Liberal MPs who supported her bid orchestrated a tactical vote against her in an effort to keep Peter Dutton from power.

Bishop had put her name forward on Friday to replace Malcolm Turnbull as Liberal leader, making the leadership spill a three-way contest with then-treasurer Scott Morrison and the former home affairs minister, Peter Dutton.

But Bishop was knocked out ignominiously in the first round after securing just 11 votes out of the 85-member party room.

It left Morrison to prevail in the second round of voting against Dutton, 45 votes to 40, making Morrison Australia’s newest prime minister, to the surprise of many.

But group chat messages leaked to the ABC show why Bishop performed so poorly in the first round of voting.

Screengrab of leaked WhatsApp chat from Paul Fletcher, the urban infrastructure minister. Photograph: ABC

The messages show Liberal MPs were warned that some of Dutton’s supporters were rumoured to be throwing their votes behind Bishop in the first round of voting to ensure she would beat Morrison and Morrison would be forced to drop out of the contest. Morrison would then throw his votes behind Dutton, in the second round of voting, and Dutton would ultimately prevail over Bishop.

The MPs in the group chat were warned they shouldn’t believe the rumour, and they should all put their votes behind Morrison in the first round of voting because he had a better chance of beating Dutton in the second round.

The Whatsapp group name was called “Friends for Stability”.

In the group chat, a message from Paul Fletcher, the urban infrastructure minister, warned:

“[Senator Mathias] Cormann rumoured to be putting some WA votes behind Julie Bishop in round 1. Be aware that this is a ruse trying to get her ahead of Morrison so he drops out & his votes go to Dutton.”

“Despite our hearts tugging us to Julie we need to vote with our heads for Scott in round one.”

Screengrab of leaked WhatsApp chat between Liberal MPs. Photograph: ABC

Someone in the Whatsapp group said: “Someone should tell Julie.”

The list of names in the Whatsapp group, as reported by the ABC, includes: Kelly O’Dwyer, Julia Banks, Julian Lesser, Lucy Gichuhi, Simon Birmingham, Scott Ryan, Christopher Pyne, Paul Fletcher, and Craig Laundy.

Senator Cormann has flatly denied the rumour, telling Guardian Australia: “This is 100% incorrect.”

Screengrab of leaked WhatsApp chat between Liberal MPs. Photograph: ABC

Bishop, who served as deputy Liberal leader for 11 years, has resigned from cabinet, but says she has made no decision on whether she will stay in parliament beyond the next election.