Danica Patrick says her plans to make her final two competitive racing appearances in this year's Daytona 500 and Indianapolis 500 are taking longer than expected to come together and be finalised.

Patrick, 35, announced in November she would retire from motorsport in 2018 after losing her NASCAR seat with Stewart-Haas Racing, planning to sign off after final appearances in the Daytona NASCAR race and the Indy 500.

With the Daytona 500 six weeks away, Patrick is yet to finalise plans for her final NASCAR appearance or a last shot in the Indy 500 on May 28, and admitted in an interview on Thursday it was taking longer to resolve than anticipated.

"It’s taking longer than I’d like it to take, I’ll be really honest with you. I thought it was going to be a quicker process," Patrick told SiriusXM NASCAR Radio.

"You can’t rush things. I’m a big believer, more and more all the time, of letting things flow and letting things take shape in the way that they would.

"That’s kind of why I ended where I ended with finishing up [my] full-time career last year, and doing the Daytona 500 and Indy 500 for this year.

“I didn’t push anything and I let things flow and it turned out to be just perfect. Honestly, I’m excited and just so grateful."

Should Patrick secure a drive for the Indy 500, it would mark her eighth appearance in the event, having recorded a best finish of third for Andretti Green Racing in 2009.