The Australian Christian Lobby has thanked Opposition Leader Bill Shorten for playing a "helpful" and "important" role in its plan to stop same-sex marriage, after Labor committed to blocking the Turnbull government's proposed plebiscite.

ACL managing director Lyle Shelton, one of the highest-profile campaigners against marriage equality, enthused that Mr Shorten had delivered "the gift of time" to same-sex marriage opponents by torpedoing the planned February 11 public vote.

"We have a plan to win the marriage debate and yesterday Bill Shorten played an important and helpful role in that plan," he wrote in an email to supporters.

"We now have more time to continue building our campaign, more time to build our coalition, and more time to win the hearts and minds of millions of Australians.