The special arrangement, due to be announced next week, would involve BT personnel on an appointments-only basis. The approach was demanded by the RUC, which said door-to-door visits by Channel 5's own retuners would be unwise in the security-conscious province.
The terms of the agreement have yet to be finalised. The two sides were still negotiating a contract yesterday.
The news emerged as the Independent Television Commission formally confirmed it would accept a delayed launch for Channel 5, which is now likely to be on British television screens by 30 March, rather than 1 January as originally planned.
The delay is linked to teething problems in the retuning of millions of VCRs, made necessary because of likely interference from the Channel 5 signal. And the award of an additional frequency for the signal has increased the number of sets requiring retuning.
David Elstein, chief executive of the channel, said yesterday that the official start-up date would not be announced for some time. "Why should we say now what our launch date is, and then have our competitors aggressively schedule against us?" he asked. He said the launch was likely to take place on the Easter weekend, but added: "Our competitors will have to schedule on Friday, Saturday, Sunday and Monday, because they won't know exactly when we launch."
Mr Elstein hinted that there may be delays in starting the service in certain parts of the country, as a result of the retuning schedule. Under the terms of its ITC licence, Channel 5 can only begin broadcasting in a given transmission area once 90 per cent of homes have been retuned.
He said discussions had begun with BSkyB to secure a satellite transponder for Channel 5, but no agreement had yet been reached. He said, however, that he expected satellite capacity to be found by the end of this year, well before the expected launch.