Premier-designate Jason Kenney says he's on board with the federal government's decision to extend its own deadline for a final decision on the Trans Mountain pipeline expansion project.

In a statement on Thursday, Natural Resources Minister Amarjeet Sohi said a decision will now be made by June 18, to give more time for Indigenous consultations, a sticking point in the project's development.

Speaking at Government House in Edmonton, where he met with Premier Rachel Notley to discuss the transition of power, Kenney said Prime Minister Justin Trudeau informed him of the delay when they spoke by phone on Wednesday.

"He told me that the advice from government legal counsel was that they needed an additional two weeks to ensure a proper completion of Aboriginal consultation on this do-over that has been ordered by the federal court," Kenney said.

"I agreed with the prime minister that they need to make sure that they cross every 't' and dot every 'i' when it comes to discharging the federal government's duty to consult.

"We certainly don't want them to have to go back to the drawing board a third time on this. And we will continue on our part to build an alliance across the country that supports TMX and other pipelines.

"We will continue to communicate the urgency of this to all Canadians."

At her own news conference Thursday, Notley called the delay "disappointing."

"We know, as I've said all along, that they need to do their homework on the consultation and the accommodation, to make sure that the decision that they ultimately make — presuming that it is one in favour of the pipeline — withstands any further legal challenges," she said. "So, if they need to do that for that reason, that's good."

Kenney's first 36 hours as premier-designate have not been positive, Notley said

Since the United Conservative Party defeated the NDP in Tuesday's provincial election, Notley told reporters, Ottawa has announced a delay of the Trans Mountain decision, Quebec has "doubled-down" on its opposition to Energy East, and B.C. has "doubled-down" on its support for Bill C-48, a federal government bill that would ban oil tankers from docking along B.C.'s northern coast.

"I think what it does demonstrate is that it's not as simple as having press conferences and expressing people's outrage over and over," Notley said. "This is a complicated country. It involves considered diplomacy and strategic pressure in a thoughtful way.

"We will be keeping a close eye to making sure that [Kenney] engages in that considered diplomacy/strategic pressure for the benefit of the pipeline, not grandstanding for the benefit of political outcomes."