The Canadian partner of ShelterBox has split from the Cornwall-based charity.
ShelterBox Canada executive director Don Ohlgren has set up Disaster Aid Canada, saying he can deliver a cheaper version of the disaster relief box.
UK charity founder Tom Henderson said that the situation was a "distraction" from the business of saving lives.
Each £490 ShelterBox contains a 10-person tent, blankets, water purification tablets, cooking equipment, tools and a stove.
Disaster Aid Canada said it had left the ShelterBox Trust to carry out its own programme.
Members of ShelterBox's response team in Canada said Mr Ohlgren announced two months ago that he was taking unilateral action to set up his own distribution system to deliver a cheaper version of the famous disaster relief box pioneered in Cornwall more than 10 years ago.
Disaster Aid Canada's Family Box costs 750 Canadian dollars (£460).
Mr Henderson said that the move meant that, instead of getting people and boxes into emergency zones, the ShelterBox Trust, the charity's international umbrella organisation, was having to talk to lawyers.
He said: "It is a distraction and anybody would be foolish to say anything else.
"But that's the business we're in, saving lives, and we're focused.
"If we look at the hurdles we've had to overcome, whether it's getting people into North Korea and Myanmar recently, it's a small hurdle.
"There's much to do and we intend to get on with it."
Lawyers for Mr Ohlgren said he could not comment because of a legal undertakings with ShelterBox in the UK, pending an attempt to settle the situation through mediation.
The two sides are due to get together on 1 and 2 September in Vancouver.