Mr Davies said the comments by the two high-profile Liberal Democrats added weight to calls for the undergrounding of the power cables or the scrapping of the scheme.
Tory Mr Davies said: "Up until now I've always believed the Liberal Democrats are in favour of the proposal but suddenly in the last two weeks we've had the Deputy Prime Minister and Lord Ashdown coming and calling for the line to be undergrounded, which is the same thing as scrapping it in my view.
"It would cost an extra £400 million to run the line underground and we know National Grid will not do it.
"If I can have my political opponents and the Deputy Prime Minister come into my constituency and say this, then it adds weight to the argument.
"I've written to the chairman of National Grid to ask him bearing in mind what Nick Clegg has said to look at his position again."
The power line is planned to run 33 miles from the substation at Cefn Coch, where the power will be fed in from five proposed wind farms, to the main power grid just north of Oswestry.
National Grid has said the cost of the line on pylons would cost £178 million, whereas running the whole line underground would cost £562 million. Currently the plans include a short section of line to be run underground at Meifod, near Welshpool.
"I'm an implacable opponent to the scheme," Mr Davies said. "I was heavily criticised for the last five years but now I feel the majority of people agree with me.
"It helps to heal wounds if the other political parties come on board as well now."
Lord Ashdown praised the natural beauty of Montgomeryshire when he visited the county last week, and said it would be "stupid" to build pylons across it, while Mr Clegg also said that pylons were not in keeping with the "fabulous countryside". and said they would be "an eyesore for local people".