The Alberta Liberals have chosen MLA David Swann to be the party's interim leader over a caucus colleague who pitched co-operation with the centrist Alberta Party in the next election.

Swann says he argued before a meeting of the party executive in Calgary on Sunday that there isn't time before an election call to make arrangements with the Alberta Party to join forces for the vote.

He also says it would also be confusing for voters, noting the Alberta Party appears to have been bolstered lately by the collapse of the right-leaning Wildrose.

Alberta Liberal Laurie Blakeman released a statement early Sunday saying she would agree to be interim leader on the condition that she be permitted to negotiate a deal to co-operate with the Alberta Party, and eventually merge with it.

She says a deal would allow the parties to nominate candidates in the constituencies they can win, and to "prepare for and run an election together."

Former Liberal leader Raj Sherman announced last week that he was stepping down and wouldn't run in the next election.

"It's too late with an election likely to be called within the next month or six weeks," Swann said about Blakeman's plan during a phone interview on Sunday afternoon.

"There's some concern, and certainly it was expressed today, about who's making decisions in the Alberta Party, where they stand on some key policy issues, and how it is that the Wildrose feel comfortable in the Alberta Party."

Swann said any substantive discussion of co-operation or merger with the Alberta Party would need to wait until after the election.

He said he is not interested in becoming the party's permanent leader, but that he is hopeful that Blakeman will consider the job when the party sets a date for a leadership convention.

Premier Jim Prentice has not ruled out calling an early election this spring despite a law mandating it be held in 2016.

The Liberals only have two MLAs in their five-member caucus running again -- Blakeman and Swann.

Swann said he will lead the party through an election if it happens this spring. If it happens in 2016, he said the party will have another leader.

Blakeman argued in her statement that it would be possible to create a joint slate of candidates for both the Liberals and the Alberta Party, with one candidate representing the interests of both parties in each constituency.

"I don't believe it's feasible to create and register a new political party before the next provincial election," Blakeman said in the statement.

"We will need to work with the Alberta Party to determine what kind of model for collaboration and amalgamation is feasible in the short time available."

Blakeman said a memorandum of understanding would need to be signed. After the election, she said the parties could discuss a union.

Alberta Party Leader Greg Clark stated last week that he was "open" to some form of co-operation with the Liberals.

Alberta Party spokesman Alex Middleton said Sunday that a statement would be released by the party later in the day.

The Alberta Party ran 38 of a possible 87 candidates in the 2012 election, took 1.3 per cent of the popular vote and failed to win a seat.

However, Clark finished a strong second to PC cabinet minister Gordon Dirks in the Oct. 27 byelection in Calgary-Elbow.

Swann said he spoke with Blakeman after the party's announcement on Sunday.

"We are both committed to seeing alternative government and alternative candidates and are absolutely on good terms as we head into the Legislature," Swann said.