Gibraltar has been under dispute for 300 years
Peter Caruana said the Gibraltan government would be more than willing to take part in talks in which all three parties had equal voices.
But he accused Britain of "booby-trapping" his chair at the negotiating table and said the Gibraltan government would reject and condemn any deal drawn up between the UK and Spain.
Talks on the future sovereignty of Gibraltar have been ongoing for several months but Mr Caruana believes his people are not being given enough of a say in the proceedings.
The British-Spanish plan is to agree a "declaration of principles" which would then be voted on by Gibraltarians.
'Stitch-up'
The actual principles agreed by the UK and Spain would however remain in place regardless of the outcome of the referendum.
Mr Caruana believes the proposal is a "stitch-up" which he is not willing to accept.
"I am committed to not take part in the talks whilst there is a danger of damaging declarations of principle being adopted," he said. Shadow foreign secretary Michael Ancram is supporting Mr Caruana's objections to the talks.
"In this process of negotiations," he said, "nothing should be agreed by any party until the overall proposals being put forward are approved in a referendum.
"In the absence of Gibraltar's acquiescence, neither government could claim that an agreement had been reached on any issue."
The introduction of joint-sovereignty is one of the issues under discussion but Mr Caruana said the people of Gibraltar wanted to remain wholly British and were entitled to make their own decisions about their future.
Ministers are keen to resolve the 300-year-old dispute over the Rock which has plagued relations between Britain and Spain since Gibraltar was taken by an Anglo-Dutch fleet in 1704.