The Canadian Taxpayers Federation says Redford called to say it will be allowed into the room where the budget is explained to reporters, politicians and stakeholders before it is released.
The federation says it was informed by Finance Minister Doug Horner's office earlier in the week that the lockup was full.
It says it has been attending budget lockups for the last 20 years.
The Opposition Wildrose offered the taxpayer federation and several others a one-day, $1 contract to attend the lockup and provide analysis.
Derek Fildebrandt, the federation's Alberta director, says he's pleased the premier has allowed the group in.
Earlier this year, the federation released a 56-page budget submission to the Alberta government.
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