He was speaking after flooding devastated households and businesses across Northern Ireland, including Newry, Downpatrick and Portadown.
Mr Tennyson said: “My heart goes out to all the families and businesses whose lives and livelihoods have been damaged by these floods, just weeks from Christmas.
“It is clear the support schemes currently available do not touch the sides of the scale of the challenge facing the areas affected.
“Shamefully, in the absence of an Executive, Northern Ireland is again at risk of falling even further behind the rest of these islands in terms of the financial assistance available. The Irish Government has already announced a substantial package of support for businesses, and last week, the UK Government introduced enhanced support for those impacted by Storm Babet.
“In the absence of ministers, the Secretary of State must now take steps to introduce business recovery and property flood resilience grants. Our high streets will also require clear recovery strategies to ensure local businesses can rebuild and repair from this devastation.”