Unite the Union says it hasn’t heard from the government since rejecting an offer earlier this week.
Bus drivers have been on strike since last Saturday due to ongoing issues over payment and conditions.
The result has been a much depleted service, with only some buses operating on core routes.
Unite’s Debbie Halsall said: “Seven days into national industrial action affecting the island’s bus service, the Department of Infrastructure has remained silent following a reduced offer made via phone on Tuesday.
“That offer was weaker than the position previously discussed and was rejected. Since that call, there has been no revised proposal and no further engagement.
“At a time when the Island is operating on a limited contingency service, responsible conduct requires active dialogue — not silence.
“This dispute can be resolved quickly through meaningful engagement. We remain ready to meet.”
The Department of Infrastructure has said it has made six pay offers to try to settle the dispute and that it has “actively and positively engaged in this discussion on the basis that some working practices change, leading to improved operational efficiency”.
If no agreement is reached between Unite and the DoI then up to 20 more strike days are planned for March.