The Israeli ambassador to the UK claimed Ian Paisley had contacted him "to obtain arms", state papers have revealed.
In June 1985 Noel Dorr, Ireland's ambassador in London, wrote a letter to his boss in Dublin on the conversation he had at a recent function.
"I expressed surprise at this since I thought it unlikely that Paisley would leave himself open on something like this," Mr Dorr wrote.
The Israeli ambassador, Yahuda Avner, said Mr Paisley was talking about "border protection".
"I said I presumed that the emphasis was on surveillance equipment rather than on arms but the ambassador did not elaborate further on the detail of the request," Mr Dorr said.
"I would assume that what happened is that Paisley may have written to the Ambassador to seek a meeting in regard to 'border protection'. The Ambassador possibly interpreted this general phrase as referring to weapons rather than technology."
The ambassador told Mr Paisley that "these things" could only be dealt with between governments.
The letter can be seen in documents held by the National Archives from the Department of Foreign Affairs under code 2017/4/78.