Robert Wilson is fighting Carmarthen West and Pembrokeshire South, which was won by Labour's Nick Ainger at the 1997 general election with a majority of more than 9,000.
But the Tories were in second place then and Mr Wilson said he expected the 7 June poll to be a three-way contest involving Plaid Cymru.
" In a close fight, as this constituency will be, I believe this technology could be the difference between winning and losing "
Now he is collecting mobile phone numbers for potential Tory voters on the stump around the seat - which stretches from industrial Pembroke Dock to the tourist areas of Tenby ans Saunderdfoot - so his back-up team can remind them to go out and cast their vote.
"There is a lot of apathy around in this election," said Mr Wilson, who is a director of the London based mobile wireless company which is providing the messaging service.
"People are making late decisions about their voting intentions and whether they are going to vote at all.
"Most people have mobile phones, and this way we can get in touch with voters across a big rural constituency."
The main aim of the text-messaging is to remind voters to go to the polling station on election day.
"In a close fight, as this constituency will be, I believe this technology could be the difference between winning and losing."
Voters who log on to Robert Wilson's website westwalesconservatives.co.uk are asked to register and leave their mobile number.
People canvassed door-to-door are also asked to pass on their number.
"We're very much trail blazing in this," said Mr Wilson, adding that thousands of people have so-far registered for the scheme.
However, he admitted that there was some reluctance among undecided voters, and people over 65 generally did not have mobile phones.
Andrew Hull from Pocket Technology, the company providing the service, said he expected this method of election canvassing to come into its own at future elections.