Two signed letters by former US president Ronald Reagan are up for sale at Swann Auction Galleries on April 21.

The draft letters, written on "No More Mr. Nice Guy" headed notepaper, were signed in 1983 while Reagan was in office.

One, signed "Dad", was written to his daughter Patti Davis, the other, initialled "RR", was destined for physician and anti-nuclear activist Helen Caldicott.

The letters are a unique insight into a political storm that occurred in1982 and 1983. In the hope of swaying her father's opinion regarding nuclear weapons policy, Davis had arranged a meeting between the president and Caldicott. A report of the meeting was published by a journalist who allegedly reneged on her promise to keep a discussion with Caldicott private.

The Caldicott collection could achieve $9,000

"I can well understand what happened, indeed I've been a victim of the same kind of unethical behaviour," Reagan wrote to an upset Caldicott.

Included in the lot are typed letters from Caldicott, one thanking Regan for agreeing to meet, the second apologising for the newspaper leak.

The collection has a high end estimate of $9,000.

Investors looking to obtain Reagan autographs can also find some potential bargains without the uncertainty of heading to auction.