It emerged earlier this week that the UK proposed to create a number of customs posts along both sides of the Irish border to replace the backstop.
It was rejected by the Irish Government as a “non-starter” and Mr Johnson later distanced himself from the so-called non-paper.
Fine Gael Senator Paul Coghlan accused Mr Johnson of running down the Brexit clock.
He said: “I’m wondering if they’re (non papers) not somewhat of an opening, or ongoing gambit on part of the British Prime Minister.
“We must remember that is playing to his own audience.”
Sinn Fein’s Sean Crowe said he was “alarmed” by the non-papers.
“The suggestion that we have this buffer zone on both sides of the border is extremely worrying,” he added.
“For me, the worry is that people in the British government clearly aren’t listening to many of us in Ireland. I don’t get the sense that they get the challenges that we’re facing in relation to the border areas.
“I don’t believe that they actually know much about the history of that area, that it was a contested area, that we have a peace process that still very much needs to be nurtured.”
Independent senator Gerard Craughwell accused Mr Johnson and his party of having “no understanding” of what a border in Ireland means.
He added: “To suggest that we might have a border 10 miles north of the actual border and 10 miles south, creating a 20 mile no-man zone somewhere between the two jurisdictions, will be a field day for every criminal and every smuggler that ever walked.”
Lacking in detail
Ireland’s European Affairs Minister has described Boris Johnson’s proposed Brexit plans as lacking in clarity and detail.
Referring to the Prime Minister’s speech at the Conservative Party annual conference, Helen McEntee said that Brexit proposals from the British government are “not compatible” with commitments made by the UK.
Speaking before Mr Johnson set out his plan to scrap the backstop, Ms McEntee said that an extension in the event of a no-deal Brexit would be “appropriate”.
She made the comments at a European Affairs Committee on Wednesday.
“I watched the Prime Minister’s speech this afternoon – (there was) no great clarity or details of any kind of a proposal were outlined in the speech,” she said.
“I think we need to wait for the official proposal to be made and for any legal documentation to be presented to the Commission and I think until that is the case, I think that much of what we are hearing is not compatible with the commitments as set by the UK themselves.
“Without any clear proposal or details, it’s just speculation and I think we have to be ready and willing to hear what it is that they might propose.
“If an extension were to be asked for, from our point of view, if we were faced with a no deal or an extension, I think obviously an extension would be appropriate.
“However, we need to know that this is not a rolling extension that just prolongs uncertainty and challenges for many industries without any clear direction as to where we’re going with this.”
She told the committee that if the UK left the EU without a deal, it would have a “far-reaching change” on the Republic and Northern Ireland, adding that risks to the Good Friday Agreement would be significant.
“Any arrangements in a no-deal scenario would be suboptimal to the backstop and would have profound implications for North-South trade, including through the impact of tariffs, checks, additional costs and administrative burdens,” she added.